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code man says my DHW tank has to go as a heat source What now? (230 Posts)
code man says my DHW tank has to go as a heat source What now?Hey everyone,
I am not going to get into the battle about DHW tanks as radiant floor heat sources as I am sure it gets folks all fired up! (though I could rage for hours about this topic)
The "MAN" says it has to go, so I am in the market for some knowledge.
Here are specifics of my system/situation:
I have a 900sq foot slab on grade, passive solar, well insulated single story structure.
The heat loss calculations I have done put me at about 28000 to 32000 btu design loss. (depending on which calculator I punch my specifics into...long form ones not the 5 question ones) But none of these take into account the solar gain.
The pex is on 10-12" centres...sitting a bit low in the concrete I suspect.
Four loops in a single zone. (the house is more open concept cottage than "house").
The current illegal heater is a 40 gallon, 30000 BTU run of the mill mid level DHW tank.
(a bit under powered, but does the job)
It gets well cold here. -22ºF is not all that uncommon.
The current system fires up in the winter on average 2 times in a 24 hr period. Three if we are hitting those super cold days. Mostly at night and early morning and only runs for about 20 minutes before it hits the set point and shuts off. I don't hear from it for another 7-8 hours.
The water in the tank - once it has sort of settled out - leaves the tank at about 100ºF and returns at about 82ºF.
Overall...not knowing much about the hows and why's of this stuff...I have been pretty happy.
BUT...I need a boiler apparently.
So I need some help with a logical choice.
Space is a major problem.
Power is a MAJOR issue. (off grid solar) Currently a single grudfos runs the whole thing. And in the dead of winter I cringe when the pump is going as I know it is eating up the power in the batteries.
I don't want to oversize this thing, but I sure don't want to find I have undersized it.
Okay, let er' rip!
Thanks everyone and anyone for your input as it is getting cold and I need to pull the trigger on this asap.This post was edited by an admin on October 7, 2013 4:41 PM.
Taking into accountthe solar gain will help with the overall annual heat load, but it's the "coldest day" on which you need almost 100% supplementary heat that matters as far as boiler sizing. Some questions:
Where is the cottage located?
Given that you are off the electrical grid, I'm guessing this is probably an LPG water heater, but please correct me if that is not the case. Were/are you using it for domestic hot water as well as space heat?
30,000 BTUs will require 4-6 GPM of flow depending on the ∆T across the slab. 900 feet of tubing in four loops would make for about 7.5' of head with a 10F ∆T or about 3.5' with a 15F differential. I'd suggest a B&G ecocirc e3-6 Vario (the bigger one, also sold as a Laing E3 Vario) which will use about 10W to pump that. If you're concerned about inverter parasitic losses, Laing makes DC variants but I don't have specific model numbers handy for those.
calculation updateHey SWEI,
Thanks for the input.
I just did this heat loss calc and came up with a design loss of 17310 btu/hr... (though I'm not sure how much faith I have in that number...but I don't know how the physics work anyway) so round that up a bit because...well...because reality might be a bit less efficient...but not much.
I am located west of Edmonton Canada...more or less 10000 heating degree days.
Yes LPG...sorry...should have mentioned that.
I have an existing Tankless unit for domestic water, but I would be open to a combo unit so I had options if the tankless craps out.
I have limited water. No well, just a 1000 gallon cistern full of rain water. So I can't waste a dropThis post was edited by an admin on October 8, 2013 11:07 AM.
the calculation for my placepdf of the calculation
pex run lengthsI dug up the pex loop numbers I wrote down on a scrap of paper and the loops I layed down have a max length difference of 14' The shortest is 222' the longest at 236'
236 feet of 1/2" PEX flowing 1 GPMwould be about 8.2 feet of head with 100F water. Too much for an ecocirc, but a perfect fit for a Taco HEC-2 (Bumble Bee -- curve #3 shows 32W needed for that flow.) A Lochinvar CDL040 would work and has a 9k minimum firing rate, but pretty much requires primary-secondary piping (needs a separate pump on the boiler, but the baby ecocirc can handle that.) The WHL-055 could handle it with a single pump, has an 11k minimum firing rate, but costs about 30% more than the Cadet. Viessmann 200-W B2HA 19 is another option with a 12k minimum firing rate.
ahhh...now I need to learn more stuffThanks for the info SWEI,
I am putting together a folder with all these products in it....looks like engineering porn.
I gather I need to get a handle on the concept of "head" as it pertains to heating and pumps. I will find a link on the internet I am sure...though the search engine may take me to a few odd places first.
Am I correct in observing that head relates to the longest run of pex in a zone and not the total combined loops in that zone? (I have one zone with three loops)
regarding Boiler sizing:
I haven't found it said implicitly, but is the idea to take your calculated design load loss and match as closely as possible to this? (this being the worst case scenario day you are likey to have to heat in...most days being much less. Because if this is the case I am thinking that for much of the time I will be barely scratching the surface of the power any boiler I get.
head lossis a measure of pipe friction. For any given pipe diameter, head loss is a function of developed length (look that one up) and flow (GPM.) In a parallel circuit, the pump has to produce sufficient head to push water through the longest branch, but flow enough to fill all the branches. The differential equations that describe all this are a bit complex, but there is plenty of software (some of it free) that can do the work.
Download and read a few of the PDFs from here (probably starting with #12) and you'll learn a LOT http://www.caleffi.us/caleffi/en_US/Site/Technical_library/Idraulica_magazine/index.sdoThis post was edited by an admin on October 9, 2013 12:20 AM.
thanks for the linkAhhhh...pretty basic....as long as you don't dig too deep into the specifics that is.
What kind of efficiency should I expect from one of these Mod con units if I am typically at the lower end of its power?
Would I expect to see the LP consumption go down or up when compared to my DHW tank that I use for heating?
Keeping in mind that my water tank was running twice a day for 20 minutes each time and this kept the house warm. Not to say it was efficient, but it was effective. I read others saying their boilers are running for hours everyday. I would freak out if thats what I am looking forward to.
Water heater efficienciesAs a heat source if it was a run of the mill basic one about 65% efficient maybe.
In a nut shell you should see improvement. The hurdle lies in your electrical consumption.
Whatcha using to harness the power? Wind, PV ?This post was edited by an admin on October 9, 2013 9:01 PM.
It's the you "should" see improvement part that concerns me.
2, 3, 4 thousand for a boiler and I "should" see an improvement.
What is all that money for then?!? To make warm water?...I was doing that for 400 bucks! I have a bad feeling about this. If I don't get the right unit this will go sideways quickly.
So, the Power is PV (solar) and If the boiler runs about as often as the water tank did/does it's not a big issue really. But if the boiler runs all the time for whatever reason it just won't work. IS there any reason the boiler would run significantly more than the hot water tank does?
The info about all these boilers doesn't even mention the standby losses from all the fancy pants computers in them.
Okay, thanks for the further insights.....This post was edited by an admin on October 9, 2013 10:02 PM.
Mod/con efficiency is maximizedwith low return water temps while firing at low rates. Somewhere near 98% on a good boiler.
Your design load could very well be 17-18k. The vast majority of the time you would need only a fraction of that amount.
The electrical consumption is a real concern. What kind of solar thermal potential do you have up there? Evacuated tube collectors may be worth investigating.This post was edited by an admin on October 9, 2013 11:36 PM.
OptionsIt sounds like your real world heat loss is less than 5K BTU. Your 30K water heater is putting out about 20K and is running infrequently.
I share your concern about the mod/cons electricity use. The fan itself is using quite a bit more than your existing unit then there is the standby loss.
Theoretically a micro CHP sounds good. It does not make much sense if you don't need the extra electricity.
Maybe a conventional cast iron boiler?
You could use a DC powered relay to cut all power to the heat system when there is no demand.
I am curious as to how they made you change your system. Did someone just send you a notice?
An interesting puzzle, keep us posted.
My statementWas meant to imply that the mod/con will be a lot more efficient. How much depends could be 30% and up.
Problem is the low load, and gas boiler sizing available to match it. Running at low end modulation all the time is a waste of a boiler. Your load is more suited to a small electric boiler, but that's not an option. Then there is the water heater which was working then now you can't use that.
I'm curious about how the "code man " got involved also. There are condensing dual purpose water heaters Polaris by htp. They are pricey, and still have the electrical drain also.
What are the consequences of not changing out the wh, and how long do you have to rectify the violation?
OkayMay sound a little crazy. Why not use the tankless you have with a HX loop to the existing water heater for the radiant, and call the water heater a buffer tank for the radiant. Your expense is a plate heat exchanger some pipe, and a efficient circulator in that loop.
Please sharewith us WHY the Code official states that it must go . There is a possibility that with some documentation and design on paper by a qualified person it may not have to . Codes and documentation in Canada are very technical .
http://www.healthyheating.com/Do-I-need-an-engineer.htm#.UlaEor7D_5oYou didn't get what you didn't pay for and it will never be what you thought it would
yes I am crazy"Interesting puzzle"
I have a whole whack of expletives that better reflect my feelings on the issue...but I am sure a moderator would redact my colourful words.
You scarred the begeesus out of me. If I was not likely to see an increase in operating cost, I would think the whole boiler industry needs to have a long hard look at itself.
The tankless can't be approved either as they are not stamped for space heating use...no amount of buffer tanks or exchangers will make the code guy happy.
The way this has come about is this:
I moved out to a piece of bare land a few years ago with the stellar plan to build myself a home. I arrived with a coffee can full of rusty nails, a hammer, saw, screw driver, a car, and a 45 year old 12' travel trailer. I got for $100. No heat, no power, no nothing.
I bumbled around the permit process a for a bit and got delayed with that, the plans the permit folks needed were delayed from the "Designer". I ended up having to walk away from that plan because fall arrived and I was no further than I had dug the foundation out.
So I moved the trailer to a sheltered spot, built a 20'x20' sort of timber frame around it, pulled a 1000 gallon water tank inside, wrapped the whole thing in vapour barrier, encased the whole thing from top to bottom in straw bales, (except for the south face, which I closed in using greenhouse polycarbonate panels for solar heat gain) I covered the structure with two industrial tarps, built myself a rocket mass heater inside the shelter, and settled in for a lovely Canadian winter. I pulled apart an old beaver dam about a mile away and humped backpacks full of that to burn in the Rocket mass heater.
Worked like a charm the whole thing did! It could be -28ºF outside and if the sun was shining I was wearing shorts inside. The wood heater didn't even have to be fired up until the evening.
So spring came and I did my own drawings, submitted them and started to build the cottage. I did everything by myself except for the concrete. Having never even built a bird house before...it went okay actually...just a slow process...Fall came around and I was just about closed in...just waiting on the delayed windows to arrive. Snow arrives still no windows. They finally arrive and the driver steps into the back of the truck and unhooks the strap on the 16' triple glaze patio slider and I watch it topple over and almost kill the driver. I had to wait another 5 months for that unit to be replaced. So needless to say I spent another winter in what I was now calling the "refugee camp". I was expecting the UN to airdrop food and blankets at any moment.
So long story short...I get to the plumbing and gas fitting stuff and I talk with a few plumbers and they tell me after looking at what I am up to that a DHW tank will fit best in this scenario. Not ideal, but will probably be better than a boiler....(didn't understand the why's and how's at the time, but I took em at face value) I look it up and sure as heck people all over the place use a hot water tank for this. Cool this is what I do then. Finish all the gas work etc. Pressure test it....works great...hmmm? I decide to throw a 20 lb LP tank on it and see how it works...winter is here after all...Works great! The floor heated up, the gas range worked the tankless unit made hot water to shower in. (after two years with no running water you have no idea what a shower meant to me)
So I get going on other house things. This brings me to today. I decide that I had better get this inspected and approved so I can get the big LP tank put in the yard and stop WAY over paying for gas. The inspector says to me that this kind of set-up is no longer approved and I will need a boiler or a indirect hot water tank rated for both space and domestic water heating.
And fair enough...if these are the rules...it's not their fault..I'm the guy who did this....I may not understand the rules, but they seem pretty inflexible about the whole thing.
So now I am trying to figure out how to make this work and still make them happy and not put myself into the position where my system no longer works (because it has been working great thus far!) just to satisfy the code.
interesting times for sure.
Purchase a mod/con boiler with controls that are low in power consumption and will run off inverter power. Triangle tube trimax boilers would work well. This option is expensive and will use more electricity than you would like. It will save on propane but you may have to add solar.
Buy an inexpensive cast iron boiler that is around 80% efficient. This is less expensive than option 1 and will save propane as compared to your existing setup. You could wire it so it will be completely powered off when not in use. You could likely use your existing vent. It would use a little more power than what you have now, but not much as it does not have a forced draft.
Fool your inspector. Temporarily remove your existing heater and replace it with the cheapest approved heat source you can find. A used furnace or freestanding stove would be a good choice. After you get your inspection, the water heater would magically reappear and you would be a happy camper. Not exactly the most honorable approach, "The man" has not left you many options.
I think this is the only instance I have heard off where a hot water heater makes sense as a radiant heat source.
InterestingThere are low load instances where water heaters in the right method are feasible.
Mans carbon foot print is minimal, and he is penalized for it in a way. By being forced into a method that uses more energy than he already does.
And I'm not so sure the ROI is there for an oversized conventional, or mod/con boiler swap being that there is not one small enough out there in his load ban. Sure a WH is not efficient, but is an oversized boiler?
Basically you need a heat source with an ASME stamp to get approval.,
So have you entertained the idea of a wood boiler? Is it approved in your areas?
Do you have the wood available on your parcel to supply it? Along with the ambition?This post was edited by an admin on October 10, 2013 7:39 PM.
Water HeatersThere are a few manufactured that are approved for space heating . AO Smith vertex is 1 that jumps to minds . 76000 BTUh , HX and 2 pumps . Probably the least expensive , unintensive labor option . Then you will have an approved unit made to do both jobs . You sound very self reliant which is a good thing , it is too bad that Johnny Government always has to retard innovation and alternate methods . Of course there are other than AO Smith that is just the first unit that I think of .You didn't get what you didn't pay for and it will never be what you thought it would
a bit under powered"(a bit under powered, but does the job)" Why did you think the 30k heat source was a bit underpowered? Does it lag changes in weather? House never gets fully up to temperature? Or 20 min is too long to be running the pump?
EastmanI'm willing to bet that this scenario is outside the normal comfort creation of a designed radiant system.
The water heater all though doing the job (to what setpoint?) is probably playing catch up mostly during its on periods. We don't know what it is set at either.
Also a 30000 btu input water heater is probably only maybe 21000 output.
A ECM circ would help his present set up with the power consumption. All though the water heater must go.This post was edited by an admin on October 12, 2013 9:27 AM.
I wonder what is really the thermal buffer here.Is the 40 gallons of extra water justifying the space it's taking up? I'm thinking the instant water heater could fire directly into the slab via the plate heat exchanger.
BufferMay give him some wiggle room on when he uses his circs. Being he is strapped for power.
I beleivethe problem may be with documentation of the system gentlemen . Canada had the same problems with bad design that we have and at present all jobs must be engineered / designed / approved and I mean if you install a different circ than what is on the plan , YOU FAIL , Period . Not sure this is what is happening but Canada embraces innovation as long as it can be shown to be sufficient . there must be some issue with the install .You didn't get what you didn't pay for and it will never be what you thought it would
I'm sure it is RichAnd thats why my post on using the tankless with an hx wont fly either.
forgive me butYou said you don't want to go into it but I'm curious why you mustn't use a water heater for heating?
I'm back....Sorry for the vanishing act, I went to the city and painted my moms house. Please remember anything I say is tainted by paint fumes.
The mod con sounds great for space..it would clean up the utility room a bunch.
The cast iron boiler could be the option I have to go with..though I dont know what the logical way to cool the water down for the floor is.
There is no fooling the inspector...well probably is, but I don't have that much energy. My goal isn't to "stick it to the man" I just want to get an LP hookup.
I have given some thought to a wood boiler, but I would like/need the option to go away for a week or two. Not likely if I have to feed the boiler. Though I do like fire...hmmm.
I will look into the HW tanks a bit more...thanks. Maybe this is a solution...My best guess will be that I won't be able to use it as a stand alone and will be forced to plumb a fixture for DHW off of it as well as the heating to make the code guy happy (I have a tankless that I really like)
Sorry, should have qualified that a bit.
I think the recovery rate on the water heater is a bit under what it could be. The temp drops down a few degrees lower than I would like it to be. But this is not based on any kind of engineering or actual knowledge...just gut feeling.
The set point is 22ºC...so 71ºF -ish and yes I feel the tank is "playing catch up"
Though from what I keep reading about the boiler set-ups, they are not without their problems dealing with a task they are not really designed to do. (heating a slab...otherwise there wouldn't be all these primary/seconday...close t's...add cold water...add warm water...mixing valves....etc..... add ons to make it work) Though I am confident I know less than nothing about how it works.
Why can't I use a water heater...I have yet to get a really really good answer.
An notable engineer involved with radiant heating in the US was cool enough to respond to an an e-mail a few weeks back when I asked what the danger is and he said he doesn't support DHW tanks because he has seen a couple of installations where the low temps created condensation and rusted out the tank.
I am not saying he is wrong...like I have said I am not an expert in any way shape or form....but I keep coming across all sorts of issues with boilers creating all sorts of chaos in slabs due to too much heat, not enough heat....condensation rusting out the guts....thermal shock....etc.
I don't know whats what anymore.
If you where me and you had to get rid of the DHW tank...what would you get?
As in what unit? how would you plumb it?
How exactly is the current system set up?22 C is the setting on a regular air thermostat, right? What is the thermostat connected to? --the pump? The pump runs and eventually the tank heater fires up?
Zmans cast iron optionI don't know what products you have available in your area. Thinking parts if ever are needed.
But ci boilers properly set up last for decades. You would mix down your supply temps with a valve that mixes cooler return water with the supply water.
I'm assuming that this install must be done by a certified pro in the industry?
You will not find the perfect match to your load with any boiler out there, gas fired that is. All though a mod/con will get close save more fuel, problem is you would never use the smallest ones full potential, but that would apply to the smallest ci boiler out there also. The ci boiler would fire at full output always where a mod/con can throttle down.
So what I see it boiling down to is how much you have to spend. Because either boiler type will get you there. Fuel will never get cheaper either.
The pump is triggered by a thermistor in the slab...(in a sleeve that is in the slab)
I have the slab temp set to 71ºF.
When the slab drops below that, the relay fires up the pump until the set point is reached. Pretty simple.
The boilers available in the area are from what I can find:
and probably a few others if I poke my nose around.
Do I need need a certified installer?...?...?
Don't know...I pulled the permit for al this and as the home owner I am allowed to do that. Will the manufacturer honour warrenty? Will I install it correctly? (though in all the things I have done with this house the gas and plumbing were without a doubt the easiest....sorry gasfitter guys...but it was really simple. I spent weeks agonizing over the how's and why's of how the gas should be done and in the end it was a matter of putting pipe dope on the threads and tightening it all together then making sure it doesn't leak.
(yes I know it is WAY more complicated when you get into more complex systems...but getting propane to a range and a water tank was dead easy.) Try moving trusses, swinging them into place and securing them as a one man operation..now that was tough!
Here are some images to give you a visual of what I did...not saying this is right, correct or logical...it's just what I did.
how about a two stage boiler?Loch has their copper tube units with stage 1 starting at 23k btus. Looks like it might be a drop in replacement for the water heater.
I can't find any two stage cast iron boilers in this size range.
What about thisHow about using the smallest cast iron boiler available and an electric water heater as a buffer tank? You might be able to find the electric water heater and maybe even a boiler on Craigslist. Just a thought.
RobMy question would be if an electric water heater as a buffer tank is legal?
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I can pretty much guarantee I don't have the powerHey RobG
I doubt that my solar panels..or more accurately the batteries...could power a high resistance load like an electric water heater for long anyway.
My little grundfos pump is my highest single load in the house at a max of 87 watts!
If I turn on all my LED lights in my house the load barely breaks 120watts.
I have no idea what an electric tank uses up...but a typical hairdryer is 1800 watts....needless to say my wife doesn't have one of those.
Not to mention I am still at a loss as to how the boiler is any better than a DHW tank when I keep seeing the boiler hooked up to a water tank....why not just have the hot water tank?
Clearly a boiler is not really designed for in-floor heat. Otherwise all this stuff wouldn't be needed.
Is there any installation where there is just a mod con hooked into a closed loop with one pump? Everything I see involves buffer tanks or heat exchangers etc. etc.
At this stage my ignorance of how this all works is obvious. I am so confused!
My DHW tank set-up is so simple
As a side note I was reading the specs on a Viessmann modcon and the "frost protection" function comes on when the outdoor temp gets down to one degree above freezing and shuts off when when it comes up three degrees above freezing. Uh...that is 7 months around here. I could burn polar bears and the last giant redwoods and be more eco friendly than that!This post was edited by an admin on October 16, 2013 8:49 PM.
The electric water heater would not be powered but be used as a buffer tank. Basically a vessel that holds water up to heating temp that the boiler heats up.
Rewind a couple posts when I was referring to using your tankless with a heat exchanger to a water heater(buffer tank) so the water heater would not actually heat the water but store it.
This was all in vane as in trying to use your present components into something code worthy would not work anyways after further info you provided.
You have a low load situation, and as of now boilers are not made that small not a usual circumstance in the industry, but becoming more usual with low load homes of larger sizes than yours in an effort to decrease our carbon foot print.
Yes boilers are very efficient and entirely for use in hot water heating, and domestic water heating via an indirect water heater . Your heating and making hot water with a 95% efficient appliance verses a 65% efficient water heater. Strictly speakingg of boilers in the mod/con category .
I think this thread got twisted into making what works for you, your load, and seemingly space and budget , and what you have from what is properly done in this industry
Your problem is you have a low load house with solar gain, and limited electrical output to really make what's available in size be a perfect match for what you have.
There are certain, and very few situations where a standard water heater used as a heat source applies. They lack the ASME stamp to be used as a heat source so you should not use it for that the code man is not wrong in his observation.
I should add the reason water heaters lack the proper certification for a heat source is money it costs more to certify for that than for just heating water to bath wash clothes, and dishes. So water heater companies just want to sell water heaters for that what you do with it once you buy it is not their problem.This post was edited by an admin on October 16, 2013 9:33 PM.
I Seeyou have Ht Products as something that is available to you . Look at their combined heat and hot water tab and see if the Versa Flame might not fit your needs . It is a high mass (55gal) mod con boiler that does not require primary / secondary (1 pump) , I would switch out the 87 watt pump you have there and install a Taco Bumble Bee (HEC-2) . This unit also has a flat plate heat exchanger that employs a pump on the boiler side to heat DHW . Not as expensive as many of the options being discussed and you're only gonna be adding about 22 watts to your consumption . Due to the high mass you can program it so that it fires minimally conserving your fuel also . tell me what ya thinkYou didn't get what you didn't pay for and it will never be what you thought it would
20 minutesMorpho, what is running for 20 minutes? The pump? The burner? Both? Does the tank run longer than the pump, or vice versa? Do you know the flow rate of the system with it's current pump?
took a momenttoday to think straight and I think I need to stay clear of the boilers and especially the modcons...too much money, too much tech, too much power needed, no service very close....shame as the dimensions are great. Probably why I keep looking at them even though I know they are not a good fit.
So a hot water tank with side in/out connections seems to be the best option. I looked at the AOSMITH vertex online and it is the same width as my current tank and 20 inches taller. I will have to redo all the water and gas lines ...and venting in my place to do it. The tankless will end up on kijiji with the old hot water tank.
Does anybody have a list of tanks with side ports for space heating?...ones that you would trust?
Anybody know if I would be looking at increased fuel consumption considering the input for a unit like the vertex is 76,000btu's? Seems a tad big for my needs....and so it begins again!.....
seems to me there is a need for a smaller hot water tank specifically for in-floor radiant.
Ahhh nevermind! either way this is the option I have if I want to satisfy code.....I knew I should have moved further away from civilization!
The pump runs about 20 minutes to get the slab to the set point.
The tank takes another 10 minutes or so to heat back up after the pump shuts off.
30 mintues?The burner runs for 30 minutes and the pump for 20?
YupMore or less...Is this a bad thing?
Look at like this...The tank fires for about 1.5 hours a day at roughly 66% efficiency.
1.5 hours X 30k btus per hour X 66% = 30,000 btus of thermal energy per day delivered into the water in the tank.
The pump runs for about an hour a day. Energy is conserved and there is basically no inefficiency loss during the transfer of heat from the tank to the slab.
1 hour of pump time must therefore transfer 30,000 btus into the slab. In other words, we can say the slab is absorbing energy at a rate of roughly 30,000 btus per hour during each 20 minute pump run.
This rate of absorption actually exceeds the net input rate of your water tank's burner. (As Gordy mentioned earlier, a 30k burner on a conventional water heater really only creates roughly 20k of usable heat.
What I'm getting at is... I don't see a reason why you couldn't hook up a boiler directly to your slab. There are cheap conventional boilers that fire close to this range and I believe include the necessary low water protection loop internally. For example, the loch copper tube one I mentioned earlier; first stage starts at 23k btus.
Problem isAnything you buy you have to look at your electric capabilities.
How many kWh can you produce, store, and use daily.
Anything that modulates, and condenses is going to use more power than your present setup because there is a fan that has to run for the combustion process. You already cringe over an 87 watt circ running to long. This is your hurdle. So you either need more storage capacity, a genset to pull ya through.This post was edited by an admin on October 17, 2013 6:24 AM.
POWER POWER EVERYWHERE.Eastman:
Oh, I have no doubts my HWT was not doing the job efficiently especially when it was one of those really really cold nights. But at no point did I find I was too cold or uncomfortable in the house. The heat loss calc didn't take into account passive solar gain...maybe that made up for the underpowered HWT? I don't know.
If it a sunny day (and the coldest days here are always the clearest) the HWT won't come on all day guaranteed! even at minus 30º
So the HWT has to go and I have options is what I am getting out of all this.
ahahahahaha! I am about to go mad.
As a side note to all this dual purpose tank business:
I contacted the government body that oversees all this and they said no problem a dual purpose tank is fine. Then I asked them if I can use it as a stand alone for the floor.
"oh no, it is a dual purpose HWT...you have to have it for domestic and floor.
So I contact the maker of the tank and they so NO! it will actually work better in a closed loop as there won't be a constant inflow of fresh water carrying oxygen, sediment and minerals into the tank. Should make the tank last longer.
Made me laugh because as it is written.... using it as a stand alone wasn't even considered for the code because it says: DUAL PURPOSE...must mean you HAVE TO USE IT FOR BOTH!...at once.
I did that mostly to point out how stupid the rules are.
I have a total of eight 260ah batteries and 2.8 kw of panels...this has proven to be enough to power everything I have with a day...maybe two of back-up if there is a total solar eclipse or the mothership blocks out the sun.
Typically I never get the bank below 65-70% and unless it is a dark day I usually get into a state of float...though dead of winter I am just finishing an absorb cycle then the sun vanishes for another 17 hours...17 long cold dark hours....why didn't my ancestors keep the wagon and ox hitched up for another couple months and headed south? I could have been a vineyard owner swinging in a hammock!
So yes there is the possibility to add a bit more load to the system...how much does a blower and computer swallow up? I contacted Loch today to find out and they had no idea what the electrical load is on any of their units when they are firing up or when they are in standby. Probably not a concern for most people.
I only put the genset to my system 16 times last winter...mostly to keep the batteries from discharging too deeply. (getting down below 50% will shorten the life of the batteries) So I guess I could burn some gas to keep my LP boilers electronics running.....THROW ANOTHER POLAR BEAR ON THE FIRE!
I can safely say a circ pump in a boiler is going to be somewhere around 60 - 80 watts depending on speed. I'm sure I can handle it....as long as the system fires up 2 or 3 times a day for 20 minutes. If the boiler has to operate 20 times a day to heat the floor then no it won't work. (not sure if the boiler will function any differently as far as run times compared to the HWT? I have no experience with a boiler...never even seen a boiler in my life, never mind gotten to know one)
Speaking of boilers....buddy of mine who is a plumber seconded a vote for a Cadet.
Anybody have one? know if it would fit my needs?
Hey, thanks for everyone input on all this by the way. It has been a huge help.
morphoI was hoping to illustrate in my last post that a heat source without a buffer tank should work on par with your current tank system. The inefficiency wasn't really my concern. The fact that your slab absorbs 30,000btu's per hour for 20 minutes at a time indicates it's a pretty good buffer in and of itself. I think you might find that your system is too small to justify the cost of condensing equipment, hence the question becomes --can I hook up a cheap conventional boiler and fire it directly into the slab? That answer appears to be yes --if you can find a small enough one. Some kind of small two stage atmospheric (no fan) would seem to satisfy your requirements.
A tank based system has other benefits though. For example, a short burn with a long multi hour pump cycle might actually save you significant pumping electricity. Perhaps somehow the tank could be forced to fire near peak solar radiation too, so you wouldn't have to store the electricity that runs the burner. Maybe some today you could hook up a wood stove to it, etc.
Gotcha Eastman...I get where you were going.
That makes sense.
Not sure if this would make the code guys happy though....I'm sure there must be something about having heat exchangers or buffer tanks or code approved fairies.....sorry. I am getting bitter about this.
Would the low temp water returning to the unit create condensation or thermal shock?
As a side note about wall hung units:
I have been reading some nightmares online about people experiences with ModCon units and how finicky they are, how they just don't last. So if the thing is only going to last 6 or 7 years lets say 10 at the outside, There is no way any gas savings will make up for having to replace it that quickly, especially after spending the premium bucks on it.
Thanks for the link. I had a quick look at those as well....most of them are way too big for my little utility room. or maybe I just have wall hung space envy.....and anything bigger than one of those looks too big now ;)
boilers and slabsSlabs have traditionally been the ideal way to buffer an on/off boiler. Problems with thermal shock, condensation, etc are due to the lack of a boiler protection loop. People that experienced these problems did not have one installed or configured correctly. I think many units actually now come with this loop as part of the boiler.(Edit: I think I am wrong here.) Finally, you would only need a heat exchanger if the radiant tubing didn't have an o2 barrier.This post was edited by an admin on October 27, 2013 2:15 PM.
one more for the "hmmmm?" fileSo while lurking around the intertubes I came across Takagi's website and it says "for space heating"
Not saying its a boiler...not say its ideal either, but why would a major company, now owned by A.O. SMITH put something like that on their website if they didn't make it for space heating and or at least know it would work and possibly have had it stamped as such?
I see...thats what the "Performance loop" is in the Loch 2 stage is about.
Wow, it's a wonder all you plumbers, gasfitters and Boiler experts can keep all this stuff straight in your heads.
i think soI haven't looked through the manual in detail, but that's what I would guess. (regarding the loch) Edit: guessed wrong.This post was edited by an admin on October 27, 2013 2:16 PM.
Tankless for space heatingif they carry an "H Stamp" they are legal (in the US anyway.) A good tankless is designed to last 20 years, as is a good boiler. The difference is expected operating hours (2000 per year on the boiler, perhaps a couple hundred on the tankless.) The tankless will only deliver its full output with a large (typically 40ºF or greater) ∆T, and modulates its output to a fixed temperature, making it unsuited to outdoor reset control.
Still , it might work in your application -- with a buffer tank.
Cadet makesIs a perfect size boiler for your heat loss 9-40k input
The code manis a Schmuck .
Here is my take on a solution that is not too difficult and fits with your lifestyle and chosen setup .
Central to this system is a Heat-Flo HF-60-D tank (2 coils) . Cast iron boiler feeds the bottom coil , water in tank is heated to 180* , this tank is your storage tank and as DHW is used it is mixed down to 115* via a Taco 5000 DHW mixing valve , when heat is required pump ( Dt) with Taco I Series ODR mixing valve on suction side gives you outdoor reset and you only use the required BTU for that moment in time . the heat exchanger for this operation is the top coil . Control is a high / low limit aquastat that shuts off at 180* tank temp and fires boiler when tank temp is 150* . Both pumps could probably be Bumble Bees that would consume a whopping 44 watts combined when really working hard .
Just a suggestionYou didn't get what you didn't pay for and it will never be what you thought it would
Not sure if the tankless is certified...I will call on Monday.
The hours of design use is referenced in their warranty section. Less than 3000 hours for the lower end models and 9000 for the higher end units. I think that is supposed to pertain to the total hours during the warranty period. 5 years on parts 15 years on the exchanger.
So if there is no difference in the amount of time it would run compared to my current HWT that would be roughly 550 hours a year.
Now if for some reason a tankless or a boiler will run more often than my HWT is running then there is no way to know how many hours I might need it to run.
Why would boiler have to run more often than my HWT...any reason?
But it is an interesting way to look at heating the water from a cost of unit perspective.
Even if the tankless craps out the 5 year mark and I replace it 4 times over a 20 year period at a cost of about $500 for the lower end unit...I still come in well under the cost of a mod con that - from what I can tell - probably won't last 20 years and will need to be replaced in that period as well.
Don't even get me started on the waste involved in this method...but you see where I am going with the perspective.
thats onother vote for the cadet. Though I had read a complaint somewhere from an installer that Loch is finicky and I should stay clear of them...
Well he isn't a shmuck per-say...he is fine and has been pretty helpful...he just follows the rules that have been laid out...but the SYSTEM IS MOST DEFINITELY A SHMUCK!
I am sure your set-up suggestion would work great....until I looked up the cost of the tank...ya...boiler and then an expensive buffer tank...plus all the other stuff puts it out of my league for sure. ( well aware you get what you pay for....but if you can't pay for it...you can't get it) And then there is the space. I can't have a boiler and a 60 gallon tank..no way. I would have to build an extension off the house to make that happen.
Going to Nicaragua for the winters is starting look more and more logical....
TakagiI don't think that the Takagi units have the H stamp. Take a look at the Navian units, they offer boiler only models. Not sure about the pricing. It has an internal pump, I didn't look at the piping diagram but I think it has to be piped primary secondary so two pumps are required. Its max electrical usage is 137 watts. That and a Bumblebee for the secondary might be a good match. They also offer a pre-fab low loss header which would make piping a snap. Here's a link.
RobThis post was edited by an admin on October 19, 2013 2:52 PM.
BumblebeeHe may not be able to get that pump. I live fairly close to Toronto, so if its going to be available, it would be here first but every supply place I went to, after they stopped looking at me like I had 3 eyes,(not many of them had even heard of it 6 months ago) said it wasn't being shipped in the foreseeable future to Canada. (it may be available now but I haven't had time to look into it lately)
mail orderHey Canucker:
Thanks for the heads up.
What I can't get in Canada, I order from anywhere I can get it.
Warranty be damned!
Ya, I'm not holding out much hope that Tagaki are certified for space heating, but it's worth a shot.
Easy fix...It's not going to conserve any energy, but if you want to get through the winter, install one hose bib on the water heater to qualify it as a "dual use" heater. If asked, tell them it's for washing mud off of your shoes...
From personal experience, I use to use a water heater for heating my house. I even went as far as installing a solenoid valve between the water heater control valve and the burner and installed an outdoor reset control on it to achieve maximum efficiency.
I eventually replaced that water heater with a modulating condensing boiler, and reduced my energy consumption by 30%.
To the untrained people who are reading this thread contemplating using the inexpensive water heaters as a dual source heater, STOP. They are a legionella generator, and unless you intentionally want to expose yourself and family members to this deadly disease, do not consider doing so.
If you want to throw a plate heat exchanger between the source and load, go ahead, but unless you are using a HUGH heat exchanger, expect it to not too work well.
Ask your code official if he'd accept your system if you throw a means of "drawing" hot water off of the tank if he will accept it as is. Just don't draw anything off the tank and you should be fine other than the major waste of fuel..
BTW, FWIW, I totally disagree with the Canadians and the American codes allowance of dual purpose heaters and have proposed a major change to the IAPMO code to disallow it. If used with a plate heat exchanger, and properly piped to avoid stagnation, I have no problem, but I refuse to allow these deadly legionella generators to continue.
The biggest problem you will have with trying to adapt a mod on into your system is the additional parasitic cost of operation, and the fact you will need to set a power conditioner for the boiler because it sees inverted electricity as "dirty" power and will probably give strange errors. There is nko way around that other than going with a conventional boiler, and then done right, it's going to be more expensive than has been quoted. You have to protect the boiler from long term condensation, and protect the floors from too high a temperature.
MEIt's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.This post was edited by an admin on October 20, 2013 2:08 PM.
Hi MarkOh.... man alive!
Is this situation that odd (save for the offgrid issue) that there isn't a well walked path in regards to a boiler choice and installation method for a smallish BTU load?
I FULLY appreciate the point regarding the health concern. I think it would be foolish to have a system where your domestic and space heating water are one in the same.
My preference would obviously be to not have to plumb the HWT into any kind of water supply at all and keep it as the stand alone closed loop system it currently is. Period.
I am fully open to installing a boiler, as long as it will do the job I need it to do and not get destroyed because it's not meant to do what I need it to do. But from what I can figure out, with the kind help and input of a lot of folks here, is that there really isn't a boiler to do it with. Save for a couple of options (2 stage boilers, or, if I am understanding this correctly, a slightly overpowered boiler with a heat exchanger.
My actions and desires are not to circumvent the codes, but the interpretation of the dual purpose HWT as not suitable as a single use heat source is utterly stupid.
Plenty of those dual purpose tanks are being used for just domestic hot water. How is this not in contravention of the stated purpose of the tank as "dual purpose"?
If I can't use it as a stand alone heating appliance and must have domestic hot water as well, how can you use it for domestic water only with no questions asked?
So, silly interpretation aside....I am totally fine with getting a boiler.
I have talked with plenty of local plumbers and they either have no answer for me or want to set me up with something I can now guarantee will fail. ( thanks for all the info everyone, otherwise I would have a massive cast iron system in here doing all sorts of stupid things ) So it sounds like a cast iron boiler will be more expensive and complicated than expected if as you say: "if done right" And I have no desire to not have it right. SO what does this critter look like? How do I protect the boiler from condensation and the floor from too high of a water temp?
As far as a ModCon and the "dirty power" I need to check with my PV guy as this is a pure sine inverted system, so in theory it should be fine with the boilers electronics...but it sure would suck to find out it doesn't play nice after buying and setting it up.
In your opinion, electrical power aside, is the modcon the way to go?
I have always been proud to say I have never been in debt in my life. If I want something, I work towards it then pay for it. I saved up for a very, very long time to buy the land and build this little cottage. I did without so many things over the years that others had so I could do this. I have been free my whole life to do what I want simply because nobody is holding anything over me. Maybe I need to go hat in hand to the bank for the first time in my life and borrow the money to do this... whatever "this" is supposed to be.
Hey Mark, thanks for your input and thoughts on this.
If it weren't for your power issues,,,I'd absolutely say that a good fire tube modcon is THE way to go. It has the ability to modulate its output down to match your load, but therein becomes the parasitic power consumption issue. The longer it runs, the more precious KW's it eats, Granted, with DCECM circs your power consumption per function will be less, but still there none the less. The inducer fan on the boiler is a DCECM motor for what its worth.
With it being a single zone, you could find an atmospheric of 50K (Burnham and others), but it won't have the ability to modulate, so it will short cycle, and the hardest thing you can do to ANY piece of equipment, is to start it up. This would require you to add storage (buffer tank) in order to give extended ON periods, and extended OFF periods and with your mechanical room being so small, probably not enough room to accommodate a tank large enough to make it worth your while.
Not exactly sure of your set up, but you WON"T be able to use the existing venting system and will have to run an approved plastic vent for the modcon boiler.
I've been told by numerous manufacturer's that a battery back up UPS is the least expensive power conditioner available for applications like these. It has been a while since I've attempted using anything with PV, so Id check with the boiler manufacturer and the inverter manufacturer to make certain they play together well,
If you did decide to go with a cast iron atmospheric, the best way to protect the boiler is with the use of a thermostatic bypass applied to the boiler inlet (Danfoss /Termomix makes one) and a 3 way non electric thermostatic mixing valve to protect the floor from too high a temperature.
It's not rocket science, but most inexperienced installers think its as simple as throwing the cast iron, or copper fin tube boiler in and turning the operating limit down to 140 degrees F, and for the most part, that WILL work, until the heat exchanger fails due to long term condensation exposure. And you still have to deal with the short cycle inefficiency issues.
The nice thing about a cast iron boiler, if wired to a line voltage thermostat, there is NO ghost power consumption. You can't do that with a modcon. At east I've never tried to do that with a mod con...
You have some decisions to make here.
BTW, it (the problem of dual use) actually has roots in the ANSI standards. Your local AHJ is just enforcing it as written. In order for it to be called a water heater, it MUST have water being drawn off at a tap., hence the reason for a tap. You can still have to pressure reducing valve, blah blah blah, but it MUST have a means of drawing tao water through the device. I agree, really a silly law, but theirs is not to wonder why, theirs is but to enforce or die.
MEIt's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.This post was edited by an admin on October 20, 2013 10:59 PM.
joining the foreign legion-ellamark. if i read this correctly, you are suggesting not to use the water heater as fully dual use in the sense of providing your domestic water, but rather to provide for a rinsing tap that would qualify the installation, but use a separate system for DHW.
I get the idea of mixing long resident water with domestic, even if the piping is theorectically 'watersafe' from a consumptive perspective has possible consequences because of the dwell time and the recirc means you are not really fully purging or drawing new water each time, not to mention that there might be other implications depending on the air content of the water for getting airbound or corrosion.
i'm with you, if i have interpreted you directly, to make the water heater conform nominally but use it for heating.
and it wouldn't surprise me that you did get 30% savings in fuel going from simple atmospheric water heater to modcon, but given his small btu requirement and limited electricity, i'd think the setup he has is quite economical and appropriate and the payback on the cost of a mod con or really any sophisticated heating appliance would not be there even if the unit lasted the expected 15 years or more.
egg zachary...Just bring it into compliance by adding a tap, but not actually using it for DHW. I agree about the economics. Hard to justify, but some people want to do the "right thing" environmentally, at almost any costs (think solar thermal, or solar PV), and setting a mod con would significantly reduce his carbonaceous foot print for a lot less money than doing solar...
Thanks for joining the revolution :-)
MEIt's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
is that like eggs benedictMark,
thanks for keeping track of all your threads.
as you might be aware from frequent, if hopefully not too snide by half comments, i'm not an any price kind of guy when it comes to carbon footprint. i'm pretty sanguine about the future of humanity (despite the shortage of plumbing techs being discussed elsewhere, http://www.heatinghelp.com/forum-thread/147454/Were-falling-behind -- after all, defending the health of the nation . . . but i digress).
i kind of treat with carbon the way i treat with swordfish. when everybody else stopped eating it that meant more for me at a better price.
so it is still expensive, there are incentives to cut down but your precise point, that a mod con would be a more cost effective way than solar is the kind of thinking i appreciate in that realm rather than less carbon at any cost approach that is crippling european industry and we're trying like hell to shoot ourselves in the foot here. Including by the way the war on industrial coal. color me silly, but i still think that advances in efficiency and pollution control for coal are better obtained at the industrial level rather than at the dispersed home carbon consuming device. that may be because home consumption of coal has gotten more passe and if the same attention were focused on the coal stove or modern coal boiler similar improvements as against efficiency and real pollutants might obtain. but given that coal is not a fluid or gas I tend to think these savings better realized in an industrial setting. that said, maybe coal ground could work in pellet stoves, although i think it would be dusty and they aren't facilitated for ash removal -- but maybe they could be. gotta keep an open mind.
whereas natural gas has proved particulay conducive to improvements in small dispersed combustion units. NG is concedely plentiful thanks to the blessed technology of fracking (which has been with us almost since oil drilling began, it is just lately a target of those who hate carbon based energy), but moving to consume any and all surplus in electricity generation will eventually place home heating in competition with industrial use as it was B.F. (before fracking -- i know i'm back to the popular conception that it just started a decade ago) So having a policy that sets up a redux of this competion where people were buying coal stoves to heat their homes in preference to gas (and fuel oil which is competition with our industrial transport fleet) and we were talking about importing instead of exporting liquified natural gas and still we were marching toward massive industrial consumption of natural gas in electricity generation with emerging anti-carbon regime. don't hold your breath waiting for peak oil, but when it really is less available, lower carbon technologies will flourish in true competition. (And of course i fully support anyone who loves technology but doesn't like carbon in making their own decisons to decarbonize at their own expense).
but of all stupid things for government to stand in the way of simple tech this guys is employing. look at his house compared to al gore's and tell me who is more of a champion of the environment and has a smaller carbon footprint regardless of whether he's using an atmospheric gas burning device. and indeed, for many in canada who aren't off the grid, they could run electric hotwater heaters off the copious hydropower.
PS - funny this should come up. just had a guy over the border in connecticut who wants to put radiant in his own house (he's a builder himself, but doing a complete gut/remodel on a house he bought for himself 10 years ago and never got to so he and his family are still living over the garage at his inlaws (don't get me wrong, it's a big garage and a pretty nice place)
So he is on a limited budget and had heard from his HVAC contracter about the idea of using water heaters to run the radiant and figured he could save the 3, 4 maybe 5 grand over his ideal mod-con plant and just throw in a couple $250 electrics and thus focus his resources on spray foam insualtion on the inside and radiant install underfloor while gutted and once he had recovered from those expenses, he could get his final plant. since it was his HVAC guy who suggested it, i imagine that the inspectors in connecticut are a little more rational than those in canada on this subject but any info would be appreciate since i told him i thought it was a great idea.
The blessed technology of frackingwas called hydrofracking and used water as the frack fluid. It was frequently used to improve production of water wells.
What we're injecting now is creating much more than "a target of those who hate carbon based energy." If it wasn't why would we need all those loopholes exempting it from regulation?
This discussion would be more appropriate in a separate thread. Want to start one?
glad to take this out in the halli gotta go work for a living. can only defend so much 'study' time each day.
got this goddamn cavernous old boiler with a conversion and its got a nice draft relief in the piping but the pilot keeps blowing out. safety rod is fine. driving me nuts to the point where i may have to break down and throw a carlin EZ gas on it.
house is slated for demolition in a year so i've just been lighting the pilot and it is never consistent. stays lit on windy days and then a week later with no apparent reason its out.
anyway i gotta deal with that so not sure which forum is appropriate. obviously fracking has been used for water wells, and long used for oil wells. and surprise suprise when they are trying to get fugacious oil and gas bearing emulsions and brine they use a little bit of oilly products in the fracking mix and everybody has their own secret slipperystuff, but i don't get too worried about putting oil into the oily ground where oil is.
Yup...I certainlydo have some decisions to make.
Is your sense that a ModCon is going to last long enough to make it worth the expense?
If it lasts only 5, 6,...10 years and I need to get another, then that is pretty bad investment. I am pretty wary of electronics and if I can avoid them, I do...but sometimes they are unavoidable.
Maybe I should stop shaking my cane at all the hip kids and their flippy dippy flashing light technology and join the parade.
With proper maintenance...a good modcon will last 15+ years. With improper maintenance, it could fail within 5 to 7 years.
Even the atmospherics have solid state electronics on them. I believe they MUST have an outdoor reset control at a minimum.
An atmospheric with a 2:1 turn down is not an efficient machine, because you can only turn down the gas input, and not the combustion air. Doing that causes the combustion numbers to go upside down due to excess air, and your fuel costs can go up.
Figure on about $300/year for maintenance into your long term program. After the first year, it may be possible to extend the service to once every 2 years, but no longer than that. That is without a doubt the biggest downfall of modcon boilers, No one (very few people) are servicing them...
What is the code problem?In my area, the inspectors have to reference the code requirements that cause a failure of an inspection. Does your notice of failure say anything about the code section(s) that were a problem or a narrative of the the reason(s) for failure? The problem here with sharing a single hot water source for DHW and space heating is the isolation of the drinking water from the space heating water. The only system I know of which is authorized to share water is the Apollo system, which uses a 75 MBTU water heater to supply a hydronic heating air handler with a DX AC coil for cooing. That water heater has side taps for the heating coil connections and the heating loop is drinking water safe.VABear
MorphoMark is the professor of hydronics.
Kind of humbled by the hose bib trick. Give it a try can't hurt. Sometimes tend to over look the obvious, and simple fixes.
no official write up about the HWTGordy:
I kinda got that impression about Mark...there was a warm glow to his post and I thought I heard the hiss of steam when I clicked on it.
I was not red carded in any official way, Like I have said, the code folks have been cool about the whole thing. I got a heads up that I was "going to need to change this before we can pass this" kind of warning. I am the one who set this up so it is my fault %100
They just said the HWT is not certified as a space heater and must be replaced with a dual or boiler. Like I said in the beginning, I don't understand the reasoning with this kind of set-up or even why a code approved tank that is only used as space heat can't be used.....ahhhh never mind! this is a circle that just gets tighter and tighter....I will get a boiler.
Just a question:
Every installation diagram I see has a buffer tank or a heat exchanger, I have yet to see a diagram showing a closed loop and a mod con boiler without a buffer tank.
Okay, I am going to bed...I've been dreaming about this stuff...so I am dreading going to sleep.This post was edited by an admin on October 21, 2013 1:34 AM.
DisagreeWith the utmost respect for Mark's professional opinion, I feel obligated to present my own hack amateur analysis that I believe leads to a complete conflict with the general thrust of Mr Eatherton's thesis.
Morpho's observations indicate that his system requires roughly 30k to 60k btu's per day. This equates to a heat source with a peak output of 2.5 thousand btu's per hour. Perhaps Morphos' observations are off by a factor of two. That implies a peak output of 5k btu's per hour. These numbers are substantially below the output minimums from any modulating heat source. What then, is the point of paying for modulating technology? His system isn't short cycling now, despite an output of roughly 20k from the tank heater. In a previous post, I also laid forth evidence indicating that his slab is capable of absorbing and buffering significantly higher thermal outputs (30k btu's per hour) at relatively low temperatures. At what heat loss can one say "you know, the payback just isn't there"? Surely Morpho's current operating costs are not too much more than the suggested maintenance budget of $300 per year for a modulating heat source?
assumptions based on assumptionsWhy over think this. Unless Morpho wants to share we dont even know how many winters this system has worked through.
What may be just fine for him to get by for comfort with his present set up may not be to you me, or anyone else for that matter. I think mostly he would like to make what he has work,
I tend to believe if putting a valve on the water heater in some believable fashion to make it work for dual use Morpho will have a waterheater for a boiler till it craps out.
And Morpho are you confusing buffer tanks for an indirect water heater in the diagrams you are looking at?
You are WELCOME to disagree with my assertions....Eastman, it is civil discourse like this that makes the Wall such a great place to hang out. Each one teach one and everyone learns from the experience,
The problem that I see with your analysis is the time weighting factor. TBtuH capacity divided by too many hours. The other thing that happens in reality is significant overshoot and undershoot of the slab, and then the flywheel mass effect kicks in and completely takes over, giving new meaning to the term MEAN radiant temperature.
Your assertion about the slab being a significant mass is correct, and improperly controlled, it WILL result insignificant deviations in the room temperature. If these deviations are acceptable to the end user, then so be it. It is not acceptable in my book and doesn't fall within my definition of true comfort, which is also subjective, and probably isn't the same in my camp as it is in yours, or other folks camp.
For the record, my definition of comfort is not being aware of your surroundings. You are not too hot, you are not too cold, you are not under humidified, nor over humidified, and you are neat hearing any noise associated with the delivery of heat/coolth into your environment, Simply stated, if you can achieve these conditions, you are truly comfortable.
Obviously, it varies form person to person, but that is the mantra I've run large companies with and it has been proven to be successful.
Having had lived with this tank style water heater, I can tell you that due to the slop in the thermostatic control valve, and the lag in transfer and pick up that I did experience significant deviations in comfort. Rarely was the home perfectly comfortable with just the tank stat in control. I tried continuous circ in an effort to smooth out the bumps, to no avail, hence the reason I (illegally) modified the heater to allow for the application of an outdoor reset control. Been there, tried that and have scars to prove it. Also, for the record, the controls I applied to this tank could NOT turn the operating temperature any higher than the tank control would allow, so it was therefore not unsafe,
With a high mass system, with the tube in the bottom (is it really possible to keep the tube within 2" of the emitting surface?) of the slab, this compounds the problem of under/overshoot. By the time the heat finally makes it to the surface, and starts satisfying the thermostat, and the thermostat eventually shuts down, the slab has a SIGNIFICANT amount of heat that IS going to come into the space, and when it does, will result in fairly significant overshoot, resulting in people standing around in their underwear trying to keep comfortable.
As has been stated by John Siegenthaler, myself, Robert Bean and numerous other hydronic comfort prognosticators, in order to achieve perfected comfort, input must equal demand in a real time basis, not averaged out over 24 hours. OK, I added the 24 hour thingy, but I think you get my drift. As for appliance sizing, industry standards dictate that the output capacity of the appliance MUST equal the heat loss calculation.
The big problem there is that NONE of the heat loss calculation programs take real life into consideration, like internal gains, solar gains and flywheel mass effects. In my own home, the load calculated out at 100 K butH. I decided to try an experiment in my own back yard, and I installed a 50K btuH heat source, and I have lived with it for over 10 years now, and have seen"design conditions" and below MANY times, and I've stayed perfectly comfortable. I've also never seen my modcon doing more than 80% of capacity under those worst case conditions... Would I ever consider doing something that brash for a customer? Not in your wildest dreams. I can't afford the liability.
As a professional, we ALL must adhere to the rules, otherwise, we can be placed in a very compromising situation that WILL cost us money out of pocket.
To my knowledge, 40 or 50 K is the smallest modcon appliance available. That's the bad news. The good news is that the ANSI standards used to reference the minimum turn down capability are finally being updated, and turn downs of 10:1 are being allowed, resulting in minimum output capacities of 4 or 5 K btuH. If this exceeds (significantly) the demand being imparted on the system, then the addition of a buffer tank to allow the btu's a place to park and standby is generally used to avoid short cycling,
Now, if you and Morpho are not hydronic professionals, it's your castle. So long as you don't create an unsafe/unsanitary condition and the work is in compliance with the code being enforced, you can do whatever you want. But if your selling the home, then it is once again subject to the scrutiny of home inspection professionals, and they may call your practices in to question, and require some sort of compensation for potential changes.
Morpho, I assumed you had a "dual" use appliance, approved for that application in your home. If it is not, you will have to purchase an approved appliance, and then throw the drain valve/tap at it to comply. The "approved" dual use heaters are more expensive than a regular tank type heater. That rule is consistent on either side of the border.
In reality, with an existing home, I'd recommend a detailed heat loss calculation be performed, AND a blower door test also be done to verify the one wild card factor we ALL have to live with, that being infiltration. One you have THAT information, then we can comfortably discuss how big it needs to be. Otherwise, its a lesson in futility :-)
Is it really possible to keep the tube within 2" of the emitting surface?If the slab is reinforced with bar instead of mesh, and if the bar is on chairs, and if the tubing is tied to the top of the bar, then yes.
Otherwise, probably not...
in complete conflictYeah, these discussions wouldn't be very entertaining if there were never any dissenting perspectives.
I'm freakin outI'm going to go rock back and forth in the corner of my utility room for a while.
That's where...I post from.
You nicely condensed my concern about the modcon not being the logical choice in this application. If only for the cost to buy and then maintain it. Not to mention the unknown longevity, the possibility that it burns itself out through short cycling etc. But the size...oh the little bugger would clean things up in that room a lot! Not worth it I know...if space were the only concern I could literally blow out the wall and make a 3 foot extension for a massive 100 gallon water heater and it would cost less than a modcon.
Concerning the cost of running my current system v.s. $300 dollars for modcon maintenance year. What I am paying is inflated because I am paying for NON bulk propane and so for two winters it has been about $795 a year to heat the place. BUT! if I can get the system approved I can buy bulk propane and it will drop to $400 and that is with the old hot water tank. Add something a bit more efficient and it will drop further. Oh I like the sound of that.
GordyYou make a good point.
What has been comfortable for me for two winters might not be for another. All I know is that I have not been cold....so I am happy...I mean if I can step out in the dead of winter and lose my fingers and ears in under 15 minutes and I step back into my house and it's toasty...I am not going to complain.
I have to replace this unit with an ASME H certified unit if I decide to go with a HWT.
And yes I will have a water heater for a boiler until it craps out.
Or if I get a boiler, some would say I have a boiler as a "Hot water heater" until it craps out.
Though I am not sure why the hwt would crap out any faster than a boiler in my specific situation. If it is turning on for an hour a day, this would be pretty typical use, if not under for a single family's HWT with three showers, laundery, dishwasher etc. So the stress on it seems minimal to me.
MarkThe system is triggered off the floor temp.... Usually set to 71...maybe 73 when it's really cold outside and to be honest I have never felt any major swings in temp. The floor is set to 71 and the inside air temp is usually about 68 or 69.
I should mention that I have plans to instal a small (if I can find one..hahaha..) Wood stove as well to "take the edge off" on those really cold nights. Want this really badly: http://www.unforgettablefirellc.com but they are costly. But they are super small and have near zero clearences.
This is as detailed a heat loss calc I could come up with. The likelihood that a blower door test could be done here is zero. I would have to pay someone from the nearest city to drive 3 hours to do it and my guess is I could probably buy a back-up boiler for the price of that service.
I feel like I should go back to school and take Engineering....except I have found myself using my fingers a couple of times on the little math thing on this site they make you do before you post...so engineering is probably not in my future. hahahahaha....
my limited personal experienceI have heated my 3500 sqft 1891 house and DHW (Elbi indirect) for 10+ years with a Takagi M1 with no problems. It is true that the Takagi takes a head loss, but the total energy usage and cost is relatively low. I have tried 2 ways to push water though it: zone pumps + DBP valve between the in/out manifolds; and dedicated boiler loop pump with a DBP. I haven't crunched the numbers for cost efficiency, but I think the latter works a little better and I can let the manifold flow without impedance.
My system is high mass and the small circulators are running much of the time in season. I have another similar installation, using a Takagi D2, that has been running for a few years without complaint. The engineering and controls are simple, inexpensive, and reliable. I am actually replacing the M1 for the H3 199k max BTU condensing ~95%. They cost about $1200, including control/monitoring panel. I'll keep the M1 as a backup but I think I got value from it (about $1.50/month capital cost for active service).
MY THEORY is that these units have been running open loop with all kinds of water, everywhere in the world, for literally millions of people. That is a tall order, so asking it to run long-cycle, closed loop, is not a big deal. Maybe it is an economy of scale that seems to beguile some - that something much cheaper could actually be better, at least in some cases?
My reason for posting is only to share personal experience, since I have learned so much by reading others'. The motives of my choices may not the same as for others, particularly professionals who specialize in hydronic systems. In my case, I chose to invest in better engineering instead of expensive products.
SWEIYa it probably is possible to get them in the centre of the slab, but it didn't end up that way in my case. I know they ended up close to the bottom...still seems to work okay for me.
my limited personal experienceremoving double post!This post was edited by an admin on October 23, 2013 6:44 PM.
MarkI stand corrected. The room temp is a pretty consistent 70 according to the lady of the house...who keeps way better tabs on the air temp than I do.
Always wise to check with the "thermostat" of the family....Cause if momma ain't happy, ain't NO BODY happy...
I suspect that the reason for your temperature stability is the fact that you are referencing the floor temperature, and not the air temperature. Good move on your part, and too bad that others don't utilize the same logic. Your tail (radiant floor) is wagging the dog (MRT).
What usually happens in a passive solar heated home is that the early morning cold calls for heat from the air temp sensing thermostat, and the heat starts making its journey from the LP tank all the way into the slab. At around 10AM, the solar gain starts getting stronger coming through the south facing windows, and the air sensing thermostat gets satisfied, BUT, there are still a BUNCH of btu's in the slab that ARE going to come into the room, and cause the room to over heat, and people to shed clothes, or open windows, or turn on air conditioners (seriously).
This is usually more of a problem in the dead of winter due to the incident angle of the sun in comparison to the vertical glazing.
Obviously, your experience may vary :-) But I have been involved in many forensic situations of discomfort that were caused by this regular condition.
Another negative we didn't talk about in using a tank style water heater for high mass systems is the rusting out of the flue liner. People assume that due to the fact that their water heater may see incoming water temperatures as low as 40 degrees F in the winter, that running it continuously at a lower temperature is not detrimental to the unit.
Bare in mind that the typical duty cycle of a DHW heater for heating DHW is less than 2 hours per day. When applied as a space heater, you WILL experience the production of condensation in the flue gas passage ways, and its not real evident because you don't hear or see any evidence of its occurring, but it IS occurring, and the flue gas passage ways are taking the brunt of the hit. Just guessing, but I'd bet that unless you experience pilot outage, you've never looked inside the combustion chamber to see how much rust is piling up on the top of the burner. And because of the fact that the appliance is actually running longer as a space heater than it is as a DHW heater, then its life can be anticipated to be less than it would be as a potable water heater. But at the lesser expensive replacement cost, they are considered a "throw away" heater. It fails, you throw it away, and replace it with another.
One good thing about the application, is that you are NOT exposing the tank to continuous supplies of fresh oxygenated water (unless you used non barrier tube in your slab) so the tank will not rot from the inside out.
Now, you probably know more about your water heater than you really wanted to.
Keep that "thermostat" satisfied at all costs :-)
Armand_ColoradoIt's funny you mention Takagi today.
They called me back and confirmed they have two units that are ASME certified, but they are WAY too big for my purpose at 380,000 btu's and 14 gallons a minute. Though I don't doubt any of the smaller ones would do what I need them to do starting at about $600. They also said the return water temp max would be 160....way way over my typical return temps of about 85- 86 -87 ish.
sorryYeah, my experience probably doesn't help you, except to the effect that what works does not always conform to what the lobbyists convince the bureaucrats to foist upon us. On the other hand, you can buy a very decent new or used boiler on craigslist. For example, here in the Denver area, there are a couple of new and near-new Lochnivar Knights between 1-2 kilobucks.
On the other hand, the cool thing about the Takagis, et. al, is that the common wisdom regarding over-sizing and cycling does not directly apply, since they modulate extremely well for flow and heat demand. I had to seriously rethink this myself since my first experience in heating was to reform ancient steam systems, which BTW, I think are under-appreciated.
Armand...No, it helps tons.......other than...I can't do it because of the codes.
This is life though.
there is a smaller ASME modelMo,
I am not necessarily advocating Takagi, since my experience is pretty limited, but they do have the T-M32ASME unit for about $1200. It is 240K BTU and ~83% efficient. Just don't run very hard water and you'll be fine. I don't know how they estimated the increase in return temperature, but you controlling the flow and output temperature is easy. Probably a dumb question, or I missed your explanation, but are you sure you need ASME for a tankless less that 200K?
ArmandThis post was edited by an admin on October 24, 2013 1:44 AM.
They didn't send that spec sheet to me!
So Armand…any insights on what it takes to make these units work?
The Asme H certification is required for the code folks.
Apparently if I have a candle under a teacup and I call it a space heater it needs an ASME certification.
Here's one ideaYou'll need 120 for the Tak, but not much draw, compared to the pump. It will require a little more pump pressure than before if in the same loop. I'd consider cranking up the output temp and use some sort of external storage tank, like an indirect DHW, to keep it from cycling too much. Then you can pulse the pumps, saving electricity. It wouldn't be hard or expensive to have a loop between the Tak and the tank, then a loop for the slab, making it super easy and cheap to control.
That setup would probably require:
- indirect DHW tank or your old DHW heater as the storage
- small pump
- mixing valve, if indirect DHW
If I am forced into using a HWTAny insights about how different hwt's would function in my situation?
lets say I put in a
Recovery of 82 gallons per hour @90º
with a first hour delivery of 155º
my current tank:
recovery of 25.5 gallons per hour at 100º
No idea what the first hour delivery is
Would I be wasting more propane?
Would it be able to keep up with the demand?
Would it be overpowered?
Any insights about what size power would work best.
This is forheating the slab, or for domestic hot water? I mean, are you looking for a dual function tank that will be actually taking on the responsibilities of your current instant hot water heater?This post was edited by an admin on October 24, 2013 2:32 AM.
Markhahaha…yes it is important to keep "she who must be obeyed" warm and happy.
The passive gain has never made me feel uncomfortably warm…yes it does get warmer in the dead of winter..but not overly warm…and it's winter and anytime I can get free heat in winter I will take it.
Question for you mark:
When you say: "People assume that due to the fact that their water heater may see incoming water temperatures as low as 40 degrees F in the winter, that running it continuously at a lower temperature is not detrimental to the unit."
When you say continuously, do you mean for hours and hours? Because this simply isn't my experience. My water heater logs an hour or an hour and a half a day.
Would you expect my system to be creating excessive condensation if I have the tank temp set to about 120ºF maybe a bit lower and once enough water has moved through the system and the tank has been forced to fire up to heat the incoming water the temp settles out somewhere around 95 and the returning water at about 83-ish.
I actually look at the combustion chamber a lot! I have to….I run the thing off a 40lb LP tank and I need to shut it down, replace the tank, re-light it. So I'm looking in there all the time.
But I am going to look extra hard now.
When you say it's good I'm not exposing it to fresh oxygenated water and that the liner shouldn't rot from the inside it peeked my interest regarding non o2barrier pex. Are you saying that the o2 that gets in through the pex can exceed the oxygen in say... city water supply into a tank used for DHW?
Yes I know more about all sorts of things than I ever really wanted to know…thanks to this place.This post was edited by an admin on October 24, 2013 2:45 AM.
Answers to burning questions...Your house is an anomaly. Your system is also an anomaly. My house is a regular, well insulated home, but not a super insulated home. My physical plant sits about 10 feet away from my office, and before I "modified" it, it would run and run and run. In fact, it ran so much, during periods of the day that solar gain was at a maximum, that I "modified" it.
I suspect your water heater is one of the newer FVIR models, and accessing the full burner for inspection and clean out can be a fairly large task. If you can get into the physical combustion chamber, look on top of the burner. THere is usually a nice pile of rust on top of the burner. This is the 1/4" thick flue pipe flaking off and accumulating on your burner.
The production of condensation is a function of return water temperatures, and time of exposure. If you are returning at less than 140 degrees F (lower for oil) then condensate is being produced in significant enough quantities that any metal components will be degraded over time. If the flue pipe is made of certain types of stainless steel, it is less susceptible to the corrosive tendencies of the carbonic acid produced. To my limited knowledge, no one who makes an atmospheric tank style of water heater utilizes a stainless steel pipe for elimination of combustion products. Bottom line, the ONLY way to avoid the production of condensation is to keep the incoming water above 140 degrees F.
As it pertains to oxygen diffusion through the walls of plastic tubing, this is probably the second least understood principle of hydronics. (Understanding the PONPC's affect on a circulators function is first). Common sense says if water can't get out, how can oxygen get in? Trust me, it does. Mother nature despises any imbalances in anything. Temperature, pressure, thermal energy and oxygen. When there is less oxygen on the inside of the pipe than there is on the outside, she does everything in her power to make them the same content. Even plastic tubing WITH an oxygen barrier will eventually balance out its oxygen content if it (the fluid) sits still long enough.
The lower the operating temperature, the tighter the molecules in the plastic pipe, the slower the diffusion.
Some plastics diffuse oxygen through their walls faster than others do, and the addition of an EVOH barrier slows the flow at higher temperatures, but its still going to experience diffusion, The only theoretical way to stop it is to use a metal oxygen barrier, hence Pex- Aluminum - Pex, and some other rubber compounds that use aluminum or mylar for its O2 barrier.
Even a full copper/steel pipe system will experience diffusion through its valve packing glands, rubber expansion tank diaphragms, rubber pump gaskets, etc.
Remember, rust never sleeps :-) And oxygen despises imbalance, and is continually looking for something to react with (oxidation) hence why rust never sleeps... It's a viscous circle, I'm tellin' ya.
We attempt to control the process by putting something in the water tank that is easier for the oxygen to eat, that being a magnesium of aluminum anode. Oxygen looks at the tank and see a softer, easier to eat metal (magnesium or aluminum) and decides to follow that path of least resistance. Problems start when the anode is completely consumed. The hungry oxygen then turn to the next harder metal to consume, which is the steel tank. So IF you have non ox barrier tubing, AND you are using a conventional glass lined steel tank (it is impossible to guarantee 100% glass coating,hence the need for anodic protection) then you should be inspecting and replacing the anode on a regular basis.
Now you (an everyone else reading this thread) know even more about your system than you really wanted to :-)
I forgot to add some thing to make you laugh. Do you know what ASME stands for? Officially, American Society of Mechanical Engineers.
Un officially, there are two meanings. Always, Sometimes, Maybe EXCEPT, or as you are going to find out, A Substantial Monetary Exchange... Have to give credit to some of my students for the last tow daffynitions... Enjoy!
METhis post was edited by an admin on October 24, 2013 9:17 AM.
Eastmanthe tank v.s. tank is for the slab.
nope just the floorI can't even wrap my head around any more than that at the moment.
If they are both atmospheric...I would suspect the higher btu model would have a significantly higher standby loss up the flue. They are both undoubtedly much too overpowered, but there's nothing really in your btu range.
One ideaHere's one idea
You'll need 120 for the Tak, but not much draw, compared to the pump. It will require a little more pump pressure than before if in the same loop. I'd consider cranking up the output temp and use some sort of external storage tank, like an indirect DHW, to keep it from cycling too much. Then you can pulse the pumps, saving electricity. It wouldn't be hard or expensive to have a loop between the Tak and the tank, then a loop for the slab, making it super easy and cheap to control.
That setup would probably require:
- indirect DHW tank or your old DHW heater as the storage
- small pump
- mixing valve, if indirect DHW
DHW heaters (tanked or tankless) as a heating sourceIt is actually possible to make these work efficiently and safely, but by the time you add the motorized mixing valve, buffer tank, and controls necessary to do so, it's going to cost more than a mod/con. Really.
Hey SWEI Huh…probably right..butIt might use less electrical power..which is still a concern for me.
Question for you…or anyone…
I have a tankless I use for my domestic use, I have it set to 120º and it does a great job at doing that. I can turn it down incrementally.
So, if I decided to use a tankless as a stand alone for the floor, why would I need to add mixing valves, buffer tank etc. If I need 100º water, I dial in 100º on the tankless and pump it in a closed loop.
If my current HWT system pushes 100º water through the floor and runs for 15 minutes, bringing the floor up to the set point, how is a tankless any different in this function? (not saying there isn't a reason. the longer I am here on this forum the more I am clear I have NO idea what's going on)
You have to rememberMorpho,
The forum is dedicated to doing things right, according to codes, proper design practice, with the utmost regard for an efficient heating system for hot water, and steam heating.
Yes a tankless, or a tank style water heater could be used for radiant, but it's not efficient to do so they are not approved for use with out the H stamp. There are better, and more widely excepted means to do so.
You could use a tankless to heat your domestic water, and heat your radiant floors with a heat exchanger. I mentioned this many posts ago, but I think you would need a tankless with an h stamp.
Still a tankless is more efficient than a tank style water heater, but not as efficient as a mod/con boiler for that matter probably a ci boiler.
Your hung up on the fact that your tank style WH was doing the job obviously satisfying your needs. With out knowing another level of comfort could be achieved if done correctly.
Another hang up is trying to make something work with the little available power you have.
You also have to remember that there are a lot of people that lurk on the wall, and to condone a method of hot water heating that is not of an approved method sets the stage for more people trying to do it.This post was edited by an admin on October 25, 2013 11:10 PM.
Hi Gordy...I wasn't saying that the tankless set up as I mentioned was proper or efficient or safe or to code. I was just wondering why 100º water from the tankless is different than the same water from my DHW tank? Why do you need to put all the other bits of equipment into the system if the floor needs 100º water and a tankless can give you 100º water.?
Doing it right, or at least as right as it can be given the parameters I have to work within is my goal as well. The codes?…I have spent the better part of 3 weeks trying to pull any info from the folks who are the keepers of the codes. I get passed around and told things like: "it will be up to the inspector to decide what is permitted" When I ask the inspector whats needed, I either get no response or I get some vague response.
One of the main concerns about the HWT (actually the only actual concern mentioned)...be it dual purpose certified or not…is that the tank will fail. But there seems to be a concern that a boiler will fail as well in my case and probably sooner than a HWT would.
I could go out and get an certified, stamped, permitted boiler and it is just as unsafe or as likely to fail as the HWT or tankless in the end.
So that means to me a boiler is not doing it the right way….for this specific situation, or maybe it is…I get all sorts of suggestions on what to do here. I know the suggestion from the code guy in my provincial government was to just put a tap on a dual purpose HWT that I will never use.
So what am I to make of the whole thing when the keepers of the code who are supposed to be looking out for the safety of the citizens of this place are telling me how to circumvent their obvious stupid rule about having to use the certified HWT as a dual use only.
I am just trying to find a solution to my needs.
I have said it before and I'll say it again, I would love to have a cool looking little wall hung boiler making my life super duper comfy. But I keep getting the impression that it will fail, and at those kind of prices no amount of efficiency rating can make up for having to keep replacing a boiler just because it is the "correct" thing to be using.
Yes there are ways to get around this issue, at great cost and complication. A large buffer tank is one that gets mentioned. But I am right back to having …for all intents and purposes a HWT….the fire just happens to be outside the tank in another unit.
So I get confused about what to do….
I tried several times to hire professional plumbers to design and instal, but from what I have read here about proper sizing…I'm better off doing it myself…because they were out to lunch! Probably just unfamiliar with loads this small or boilers in general…who knows?
At this stage I am literally thinking about just opening up a window all winter so I can get a boiler and not have it short cycle to death.
???? whatever.This post was edited by an admin on October 26, 2013 1:08 AM.
i agree that a degree of caution is in order as between conceptualizing an off label use for a combustion unit (or electric heater although that is inapplicable in this thread) and recommending it as a professionally endorsed or certified solution.
but i don't view those two as coterminus -- to use a favorite 4 syllable adjective. Indeed, several professionals recently recommended using domestic hot water heaters for radiant for a friend of mine who is a contractor, they know him, and they know it will work and they don't feel there is any comprise in safety. they are trying to help him to channel resources towards the most efficient insulation and radiant installation and away from investing in expensive heating plant for the time being. He has plenty of electric and that is actually what they are looking at. Cheap, easily replaceable. Efficient but the cost per btu is higher because of the cost of delivery. But manageable given the sophistication of insulation and 'element' he is planning to install. If the hot water heaters crap out in 5 years, he can choose to upgrade then, or just throw in another $200 unit and keep going -- looking at what actual consumption has been and the relative costs of electricity and propane (or fuel oil, think the energy fundamentals and combustion technology don't favor it for the next decade at least, but i never say never.)
So those are the professional opinions he is getting, but that is distinct from certification. I think it would be the responsibility of professionals who see that certification is arbitrarily preventing a perfectly functional and safe arrangement from being employed to propose changing those standards. Just as doctors can prescribe off-label uses for pharmaceuticals, a well informed professional -- or for that matter an educated homeowner with documenation -- should be able to work with inspectors to accomplish these ends.
In that vein I appreciate Mark's suggestion to simply add a potential domestic use to the system as a way to legitimize it -- even though he recommends against actually employing the unit for the full domestic supply -- some stupid thing about the american foreign legionella or something. There he goes thinking again.
In a sense he is using the certification against itself. If rules are rules he is showing how you can follow the rules and get this done, while also suggesting full consideration of options. That is professionalism -- not to mention paying it forward because we aren't paying him to be here.
I hope he feels that he gains much from articulating solutions and this exhange of graffiti on the wall. I certainly appreciate it, and try myself whenever i come here (or any other forum like it) with a question of my own to contribute to other threads.
so i do go through absences when i ain't got any questions and could be helping (well maybe that is too generous a characterization of my 'contributions').
I still think Mark's recommendation could be your best bet to solve problem for now while you consider your future 'powerplant'.
Tankless temperaturesthere are two issues here.
The first is one of controls. A tankless water heater's output temp is generally not controllable based on outdoor air temperature, which is how the overwhelming majority of modern boilers operate. It's also the best way to deal with a high mass emitter like slab-embedded tubing. This can be worked around with an appropriately controlled motorized mixing valve, generally accompanied by a buffer tank to prevent massive short-cycling of the heat source.
The second is one of design. A tankless water heater's heat exchanger and burner are designed to impart a huge amount of BTUs into cold water as quickly as possible. It throttles back to maintain the designed output temperature, generally within about 5ºF or so of setpoint. A modern hydronic boiler is designed to maintain a body of water within a degree or two of the target temperature, even if the incoming water is only 5ºF cooler than that number.
So yes, if you manually adjust the tankless temp depending on the weather, and fire it just when necessary, it will probably get the job done. But automating that and making it safe will cost more than buying a tool that's designed for the task. The Lochinvar Cadet CDN040 should be a perfect fit for your house (and costs about 30% less than the other candidates having low minimum firing rates.
SWEIOhhhh…that makes sense….I think.
Any idea where I can find the price of a cadet online?
I asked the plumber to spec it in his quote, but he said he won't do Loch as he finds them problematic….and he wanted to put a really large boiler in anyway. I tried to call the dealer, but I am not an installer/plumber or gas fitter, so they won't tell me the price.
And power consumption being an issue of mine, I tried calling Loch to get the specs on power use and they had no idea.
I sent an e-mail and got no response.
So as usual I'm out in the cold…ha! …see what I did there?!? "out in the cold"….I'd laugh but its just about to be true. The passive gain can only do so much and real winter is coming!This post was edited by an admin on October 26, 2013 1:07 AM.
Lochinvar CadetIs a new line, with simpler controls and lower cost than the Knight series. It's based on a Giannoni heat exchanger, which requires a bit more care in both installation and maintenance than the newer fire-tube HX designs. BUT, it modulates down to 9,000 BTU/hr which is lower than anything else on the market. It also costs about 30% less than either the WHN-055 (minimum modulation 11,000 BTU/hr) and the Viessmann 200-W B2HA 19 (12,000 BTU/hr minimum.) It's not a general-purpose replacement for either of those, but for the money, it's a nice little unit.
ODRIn Morpho's specific circumstance, I can't see where an ODR at the tankless heat source would be necessary. If the heat exchanger for the slab is sized appropriately, there would be little advantage to lowering the DHW setpoint below the typical 120's.
Of course, the heating system supply after the heat exchanger should have ODR.
ODR?What is this ODR you speak of?
Outdoor Reset ControlAn ODR enabled system checks the air temperature outside, and resets the heating system supply water target setpoint based on a simple user adjustable function.
In a nutshell, such a system delivers hotter water to the heating system, the colder it gets outside. This helps prevent slabs and other systems from overshooting/undershooting the desired indoor air/slab temperature and increases efficiency.This post was edited by an admin on October 26, 2013 1:26 AM.
PWM pump controlThere are thermostats that are somewhat useful for this. Earlier, I was saying how you can use the pump to control the heat delivery from your storage. This type of thermostat uses differential and pulse width modulation to avoid overheating your house. It is not a replacement for outdoor reset, but I'm not sure you need that anyway. The one I have was about $50 (Wirsbo WT 1). I'm not sure how much my opinion is worth though, since, according to Gordy:
1. My systems are "wrong" and have not been safe, efficient, reliable, comfortable, approved and economical, despite my experience to the contrary.
2. I am a troll, "lurking" on the wall
To be clear,this device does not throttle the pump up and down, it does not have such a capability. It cycles the pump on and off, and the heat source must also cycle on and off, and the heat load should be capable of absorbing the minimum output from said heat source.
Small loads are typically handled with something like a Taco XMB-1 mixing block connected to a DHW tank. In such a setup, the pumps can cycle frequently, deliveing precise temperature regulation, with or without ODR, and yet the tank heat source can cycle independently with its inherent buffer.
SWEI, what is cost of mixing valve as opposed to relayprobably mixing valve is a better idea from point of view of for an atmospheric gas water heater with a non-electric safety, and would slightly lessen the extent of cooler water return which could contribute modestly to tank life.
but considering that the tank in DHW service can be subject to 40 degree water entry, if you got a heater with electric ignition/control/either spark or hot surface you'd have a circuit you could control with a relay (say 501exp, hooked up to a PC-700 just to quote the TACO version but there are TEKMAR solutions too). Ditto although the relay would have to be a little more robust for electric hot water heater.
Maybe that would set you back about the same amount as the mixing valve and if you are going entry level on the hot water heater you won't get electric ignition anyway so this could be beside the point. just wondering if you have thought about that adaptation.
I'm sure they have got the mixing valves better and more cost effective, but back when i was doing floor radiant before it was popular - carelessly revealing age -- those mixing solutions were really expensive and flukey and i have stayed away from them ever since, partly favoring the isolation of an indirect tank limiting the issues of oxygen permeable piping -- polyb[ea]utiful in those days for corrosion at the heat source and allowing for higher temps at heat source vs. floor. of course the other downside is if you used a plate heater in this setup where he doesn't really have a lot of utilities space for an indirect and where the cost of indirect starts to push you towards entry level or used mod-con -- you can get old munchkins for only a little more than they charge at dunkin donuts.
Mixing downunder ODR control is well-proven at this point and it really does work better. Comfort (minimized overshoot) and efficiency (longer firing cycles) both benefit from it. A Taco iSeries-R is probably the simplest and least expensive way to get there.
If you implement it, you can change heat sources (from a water heater to a CI boiler to a wood-fired boiler or even active solar thermal) without throwing it away. It decouples the distribution loop from the heat source.
Read this if you get serious about wood http://www.caleffi.us/en_US/caleffi/Details/Magazines/pdf/idronics_10_us.pdfThis post was edited by an admin on October 26, 2013 11:24 AM.
what about the takagi remote for JRII that morpho has linkedI am not familiar with the TK-RE02 remote control for the takagi. checked their installation manual, http://www.takagi.com/download/product_manuals/T-KJr.pdf , and they have a schematic on page 20 for heating install. again, they say you may have to add other safety devices they don't show in the verbiage but they do not mention anything about 'certification'.
maybe they are think american market and not really addressing canada and this is not as much of a problem here. for once we're more competitive in our regulatory structure if that were the case . . . on the other hand we'll never access our tar sands. god bless america . . . eeer alberta.
I can't tell because they don't seem to easily link to install instructions for the remote which is very sophisticated, costs $40 and may even be included these days, and could easily house the capability for setback, but i can't tell if it does. it has in/out temperature input but that may be in coming and outgoing water rather than ambient air. unclear on that and can't find install manual. if they are going to show heating use and have that great modulation ability, i would think they would include a heating algorithm in this device, but i don't know if they do.
and while it does give you some facility to do your own setback work conveniently without sensors, it only goes down to 99 degrees which is not as useful. would be an awesome unit in combination with storage or mixing to obtain cooler temps for zone service, but it ought to have this stuff on board.
the wording that has me stumped today:This is a portion of the code that references that the heating unit must be "CERTIFIED".
My question is what does "certified" mean? Is there a specific certification from "XYZ" organization regarding dual use water heaters? (Storage or tankless)
COMBINATION POTABLE WATER / SPACE HEATING GUIDELINES
Combination Water Heaters shall be certified and marked “Suitable for Water (Potable) Heating and Space Heating”
These systems consist of a Certified Combination storage type or a certified instantaneous potable water heater used in conjunction with a fan coil heating system, baseboard system, and/or a radiant slab heating system, and intended for space heating applications of not more than 75,000 Btu/h.
Certified – (with respect to any appliance, accessory, component, equipment, or manufacturer’s installation instructions) means investigated and identified by a designated testing organization as conforming to recognized standards, requirements, or accepted test reports.
So if Takagi puts suitable for DHW and space heating on their website, does this mean they have certified it?
This unit is advertised on the Takagi site as dual use, but all those fancy certifications on this spec sheet don't mean diddly to me.
So if the code folks just say it must be certified…well I see all sorts of certifications on the spec sheet, so it has been certified….Then Takagi slaps a sticker on it saying: “Suitable for Water (Potable) Heating and Space Heating”. are we all good?
What does an ASME H pertain to?
ASME LHW?…or maybe it's HLW…this stamp shows up on a few things as well.This post was edited by an admin on October 25, 2013 11:06 PM.
i like [takag]ikenot all puns are perfect and mine always fall flat. but i've got two of the original juniors in service and i think they are fabulous. in your circumstance the stack convertiblity means you can vent in your chimney, which, if i recall is you present approach.
these are mod, but not mod-con so they don't have the true efficiency of condensing exhaust. but my experience with the first gen in DHW service has been nothing short of phenomenal. i'm sure there may be some exceptions out there, so don't take my word alone.
in the brochure you linked, i don't see the heating suitability phrasing. maybe i missed it. other response here point out it would work suitably, but that is different from certification.
if this is all about getting certiified to satisfy the propane company, how about getting 6 dozen 100 lbs cylinders and bringing your own propane out there. if you find a good supplier you might get better price for buying volume even though you aren't a regular delivery customer. Would guess that you would need two or three manifolded anyway, if they were outdoors, to get reliable delivery in the cold. the delivery folks would have sized the tank they placed relative to that demand and probably you would need a larger tank to obtain the required evaporation than to service your actual consumption. that is instinct. i haven't run the numbers.
A bit of perspectiveComfort is relative…spent two years in this:This post was edited by an admin on October 26, 2013 1:32 AM.
Mabey you should...be focusing your efforts on a wood based heat source for the floor. It seems you certainly have the DIY skills to pull it off.
As a point of reference, if one needed an average of 30,000 btu's per day for 180 days, that comes out to 5.4 million btu's (per season), or about 1 cord of wood if utilized at an average efficiancy of roughly 30%. 30k btus can be stored in 40 gallons of water with about a 100 degree temperature swing.This post was edited by an admin on October 26, 2013 3:23 AM.
And over allIt was pretty comfortable.
!Bet you didn't know there were Hillbillies in Canada.
Another approachThe human body at rest distributes 500 btus.
I see you have two dogs. I would have to say that's at least another 1000 btus.
Some assorted live stock could meet the load. The thermostat would be the occupant letting them in and out of the dwelling as needed.
Seriously though this thread is turning into creative ways and methods to side step proper design practice, and codes.
gordy, see my other response on professionalism or i'll reiteratemost of what people (perhaps other than me) are suggesting are ways to use the rules to allow him to continue to use a perfectly adequate and safe system. that isn't getting around the rules, that is following them.
as i said, mark's suggestion is by far the best, albeit if you believe that the rules bubble up the best of what the profession has to offer and somebody has been told the rules require a different combustion unit and they find a way to avoid that you may somehow think this is cyncism or avoiding the rules, i suggest it is anything but.
further, as i mentioned in previous post, as doctors can prescribe off label uses for drugs, i see no incompatibility whatsoever with that respect for medical professionals and the notion that heating professionals applying their knowledge and experience can construct safe uses for heating appliances that are not necessarily their design uses. Esp. where the number of circumstances that might employ this technique are more limited it is understandable that manufacturers don't have incentive to certify or label such approaches but that doesn't suggest that what is being discussed here is inappropriate, unsafe or unprofessional.
not to mention that this is quite obviously accepted practice in the states as it literally came up as a recommendation on a job i'm helping with from other professionals, besides this off the wall . . . occasionally on this wall . . . fellow who doesn't have a lot of respect for rules. honest, i didn't bring it up, i just chimed in and said i thought it was a great idea.
i've got respect for the dangerous, unreliable or ineffective circumstances that rules are sometimes trying to avoid, i just don't believe that the rules usually represent the only or even the best ways to avoid them.
Professionals applying their experienceon a job where they are making money and with familiar codes and inspectors is one thing. Their reputation and their insurance are on the line and they make decisions accordingly.
Advising someone you have not met, in a jurisdiction where you do not hold a license is something else entirely. If you think we're conservative, try asking a PE.
Not only thatPeople have a tendency to pick and choose bits and pieces of information that satisfy a subconscious thirst for getting a system they can afford. Not realizing that putting those bits, and pieces together in the wrong form can result in danger, and disaster. Kinda like Mentos, and a two liter pop bottle some aluminum foil.......
People come here pick and choose parts of threads to come up with their own concoction of RFH.
And in Summary….Hey guy's..or ladies…never to sure on the cybernets.
I just wanted to thank every last one of you for the input and on thoughts and design ideas.
Code approved or not.
My stated goal this whole time was to do what was safe and code approved. Several options were presented that "twisted" the codes intended meaning. i.e. Marks single, never to be used tap. And as I mentioned, the Government folks here in Alberta reiterated this approach as a solution as well.
But my intention isn't to pull one over on em', I just want to make warm water and push it through the floor in a code approved safe way.
If that involves a dual purpose tank cool. Or a Tankless unit that is approved and that functions well ….well thats cool as well.
If I can get a boiler that fits the need and doesn't mean I drive my car and waste gas getting to a second job so I can pay for my "efficient" boiler and it's ongoing maintenance…well thats cool as well.
All my questions regarding Tankless or Storage type systems was to understand the reasons they are or are not a good choice and why. Same goes for my dumb questions about boilers. If I had gone with the local suggestion from a gas fitter I would have a massive boiler that would be shot in no time flat. So this has been a great exercise for me to educate myself about the limits of what is possible, what is efficient, doable, safe and ultimately what will be code approved.
Exactly where do I put the "outgoing" and "incoming" copper lines in the dogs?…….oh…..nevermind.
Come here Abbie…good dog…stay still……
One basic decisionwhich you really should make at this point is whether you intend to use a non-modulating heat source going forward. The means pretty much anything other than a gas-fired mod/con boiler or a modulating electric boiler. Wood, coal, solar, or a water heater (tanked or tankless.) If so, you would be well-served to install an ODR-controlled mixing valve like a Taco iSeries-R. It will serve any or all of those heat sources, even combinations of them. If you decide on a modulating boiler, it will come with ODR controls onboard, which will obviate the need for this (and save you about $300-350 USD.)
Best of luck with your system.
No tubing neededThey are there own contained radiant heat source. If you want more output just play fetch for an hour.
Sorry just being facetious Morpho . But have you ever been in a dairy barn milking cows?
hot water from compost pilehttp://www.motherearthnews.com/renewable-energy/compost-water-heater-zmaz81jazraw.aspx#axzz2itSsqGMY
What solution are you leaning to?Just curious what people get out of these threads.
Dairy cows in my house!? No way!
I prefer goats.
I read a book by a lady about how she built a greenhouse and she kept chickens if I remember correctly in it. She had their BTU output all factored in. Pretty cool stuff.
I think it was called SOLVIVA…one sec…… http://www.solviva.com.
Funny you should mention compost heat. I have read a bit about it, but I can't get my pile up past 90….100 My goal is to get her into the 140 range so I can kill off the weed seeds etc, but I just can't get the carbon/nitrogen/moisture mix right.
When I checked the thermometer a couple of days ago it was about 80 and falling.
My plan was to use the compost pile to "heat" the cistern water in winter so it doesn't freeze up or get too cold for my tankless. But this hasn't proven to be a problem thus far. The water seems to have enough thermal mass and it is inside a passive solar greenhouse that gets pretty hot during the sunny winter days and over two years it hasn't frozen yet. (Fingers crossed)
What am I going to do for a boiler you ask?
I don't know. I thought I knew. Last night I was dead set on a CI boiler because it is low(er) tech compared to the Modcons, less power, probably less expensive to maintain etc. But they are all pretty much over powered for my needs.
Modcon? Power hogs, Pricey, maintenance, unknown lifespan, even finding someone to service the thing will be a problem way out here. But space savings would be great, a few of them fit closer to my load minimums and the corrosion is less of a problem.
The HWT is still possible, but I really don't like the idea of having to have it hooked up to the domestic water in any way shape or form. It takes up a bunch of space and I don't like the idea of having to be worried that the guts are rotting out of the thing. Easier to replace parts on CI boiler if they are corroding. I could drop big bucks on a stainless Polaris tank, but that requires big bucks!
Wood? I would consider it if I could get my neighbour to come by every day for weeks on end to feed it while I am away. Not likely. They are pretty expensive to buy and instal as well.
Tankless? I think it would work, but the cost on a certified unit puts me in the range of a CI boiler (maybe more once funky controls are added) and I'm not sure it would work any better. And there isn't much in the way of service techs once again.
So, what did I get out of this forum experience….
I can at least speak to the problem with a slightly more rounded understanding.
Rounded…rounded…kinda the same meaning as obtuse. Hmmmmm?
Small CI boilersdo exist.
Chris pointed me at the Crown AWR038 awhile back, which is supposed to tolerate 110ºF return temps. Too bad they don't offer a high altitude version or I'd be using them regularly here.
I am too high…just a bit2421 feet above sea level is where I am at….Maybe if I dig a pit 400 feet deep and drop the boiler down there it will work!
Whats the worst that could happen with the boiler at 400 feet above the altitude limit?
I see in the states they just de-rate it by 4%…hmmm….maybe I should be building a tower, not a pit!
Anybody ever built an 8000 foot tall Boiler stand?
follow up on earlier suggestionFYI, I looked through the manual of the loch solution I had suggested earlier. From my reading, the "performance loop" protects the unit from low system flow conditions, but not low temperatures. So some kind of low temperature protection method would be a necessary addition.
Performance Loopas I understand, it was originally intended to deal with both flow and return temps, but did not perform as they had hoped. Page 27 of the IOM does give conditions under which it can be eliminated. I'd do that and install a thermostatic boiler protection valve (which we now specify for all conventional boilers.) I like the 2-stage firing -- would sure like to see more of that in the market.
How about thisI think everyone agrees that what you are doing is operating safely and doing so in the best way possible for your situation. Until the manufactures catch up with the low BTU's required for these new highly insulated homes you are stuck (the power needs of your home are a whole different issue) The codes for your area just do not take into account for your unique situation. Using a water heater as heat source is commonly done here in the U.S. , many jurisdictions still allow open systems doing both domestic and space heating.
That said, how about using a vented gas wall heater and call that your main heat source for inspection. Try leaving the radiant hooked up for the inspection and tell him that it is just a project you are working on. He may make you disconnect the water heater but a couple of pex couplings to reconnect the radiant is a cheap price to pay. When boilers finally catch up with the lower BTU needs of many, you can always replace the water heater. As a bonus, the direct vent units will work with no power. If your solar ever goes down you have an alternate heat source and freeze protection.
Just a thought.
Just do a search on Google under "vented gas space heater" and you will find plenty.
I was just about to suggeston of these http://www.rinnai.us/direct-vent-wall-furnace
loopEastman - SWEI
Thanks for the info guy's……
RobG - Huh…I will look up what these are about.
ThanksThis post was edited by an admin on October 27, 2013 4:59 PM.
Does anyoneHave a good link or a thread to look back at that explains the hows and calculations for using a ci boiler…lets say a run of the mill "small" 50k btu unit. running into a heat exchanger….so that the other side of the exchanger is supplying the desired temp for the floor and keeping the system water and the boiler water separated.
A constant one water temp kind of set-up. Nothing fancy, nothing involving computers or power.
You guys know what I mean…I just can't explain it well.
Yes I am positive the boiler will short cycle…(unless you have a way up your sleeves to cool the water going back into the boiler…but not too much as that makes it condense….)
just to clarifyDo you have o2 barrier tubing?
Heat exchangerIf you install a reverse indirect, it will get the job done and provide some thermal mass buffer for the boiler.
You just reached the point where I believe it will actually to be cheaper to install the mod/con.
Mixing valveJust run the water through a thermostatic mixing valve. It just has a manual knob to adjust the fixed temp to the slab. The boiler will be oversized so I don't think it will condense.
You will be running the floor water temp a bit hotter than normal in order to reduce the heating cycle length and save electricity. You will see some overshoot of the t stat set point, that is the trade off.
You have a very unusual condition that calls for some compromises and unusual solutions.
and there is the problem...….well one of them anyway!
I didn't know at the time to even ask about o2 barrier pex. It wasn't anything to do with trying to save a buck or anything….I simply didn't know any better. The loch solution has copper fin…maybe that will make it a bit less likely to be an issue?
But this is life, Its in the slab and thats all there is to it and I will have to design around it.
That dang Cadet begins to look good once in a while….actually a lot.
A comedy of errors around here. •••hanging my head in shame•••
How big an issue has this actually been for people?
Has this not been a problem long before pex appeared?
Was it just a fact of life and taken as a given?
o2I suspect it's not a big deal in small low temperature system like yours, but I think this information is something that you would want people to be aware of as they provide feedback.
And once again, are you saying the tubing is not o2 barrier, or you don't know if it is or isn't?This post was edited by an admin on October 27, 2013 8:21 PM.
BUBBLES!Not o2 barrier.
well, not to worry about the O2 barrier . . .. . . you'll be rotting the tank from the inside (dissolved oxygen) and the outside (exhaust condensation) at the same time. I'm still a fan of RobGs solution. find someone who wants a propane wall heater. put that in. get your propane delivered. then go back to you old system. high 5s rob.
because you don't have oxygen barrier tubing, that should tip you in the long run, towards a storage tank with a heat exchanging coil that separates the water in the floor loops from the water in the boiler/heater. And this will allow you more flexibility to use small CI boiler or say an old heatmaker which is very servicable low mass boiler but not modulating or condensing. i think the lowest firing rate was 60,000m. or i did find some cute little cast irons , http://www.younits.com/boilers-c-163_168.html?buto=40000&bufrom=30000 , including the Crowns mentioned already in this thread, but also a 'new yorker' at 27,000 btu which is nice and small and would team with a storage tank nicely.
One advantage to cast iron boiler for your situation is that, same as the hot water heat you are using, negligible or no electric consumption. The heatmaker or any mod-con will consume power because it uses fan forced combustion air. now that is one thing not mentioned in the blower door test question. you need makeup air for the atmospherics - the modcons and heatmaker use outside air.. probably your house is not so tight that this small burners can't do it, but that is another reason to stick with a relativley low btu heating plant if you are going to stay atmospheric.
but the 27000 btu CI atmospheric at $1200 -- and i would think you ought to be able to find it a little cheaper than that, i didn't even look too hard -- ought to be a lifetime boiler if you separate the floor water and the boiler water with a storage tank. you might need a little clever piping to try to keep return temps from being too low that might actually start to look a little sensible. and on electric consumption side, you'd only need the boiler pump loop the hours the boiler is running and those hours would be minimized with more btus and storage.
but far be it from me to discourage you from just planning to buy a $300 hot water heater every 3 or 4 years and keep on trucking with what you've got; and if you can't get the propane company happy with delivery what about the other idea i had, i.e., getting a half dozen or so hundred pound cylinders and finding a propane company that would give you a bulk price for filling those all at once?
just because enquiring minds want to know, what does your $800 current bills and $400 expected bills under bulk contract actually amount to in terms of price per gallon or per pound?
And here is some sage advice from MORPHOAnyone who is following this thread or who may stumble across it in the search for info about the how's, why's and what's of radiant heat design and execution.
1. Read a lot and make sure you have all your ducks in a row. And then read some more and epoxy those ducks in place!
2. Find a pro and pay em for their vast experience and Knowledge.
3. Apply to University…don't….I repeat DON'T take liberal arts…get an Engineering Degree….design your heating system….post answers to heating help.com to save dumb people like me.
Figure I'm to that place huh?
I'd have to figure out what the ongoing maintenance cost of mod con is. Plus the price difference between a CI boiler.
What the cost of just either replacing the exchanger on a CI and/or just replacing the CI boiler after ten years…….hahahahaha….I'm sorry! It's a habit. or maybe just bad genes. Maybe both.
No o2 barrierIs not a loss you just have to design around it. That means isolating the boiler from the tubing via heat exchanger.
Or using non ferrous components. Ss, or bronze circulator
And or using a boiler with a ss hx.
If you don't the oxygen that diffuses through the non barrier tubing will corrode all the ferrous components in the system over time. There are o2 scavenger treatments that can be added to the fluid in your system also.
Most boiler manufactures have notes about the use of non barrier tubing voiding warranties.
As a side note ci boilers are very robust when properly installed.
Mod/ConWith the O2 issue, the mod/con just moved up on the list. When you figure both the cost and the electrical usage of adding the heat exchanger and associated expansion tank, piping, air eliminator and circulator, a mod/con with a stainless circ and expansion tank is looking pretty good. The O2 is not the end of the world, just one more thing.
understanding o2 diffusionhttp://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDgQFjAC&url=http%3A%2F%2Fwww.mrpexsystems.com%2Fpdf%2FDiffusion.pdf&ei=uOhtUqm1Kebg2QXk_oG4DA&usg=AFQjCNHWNHKT2jqqYPTXiNpRqwLkug5zAQ&bvm=bv.55123115,d.b2I&cad=rja
How bad of a problem is this? My search came up with a Mr Pex doc that references a lot of German/euro research.
Quoting the above referenced doc:
"Experience from heating systems have since long established that corrosion levels in hydronic systems with ferrous metals are acceptable at the level one exchange of the system water (to fresh water) per annum."
Apparently this is about .05 grams per cubic meter per day. Regular plastic without the o2 barrier let's in much more. The following is based on a water temperature of 104 F.
"Typically, non-barrier plastic tubing allows about 5 grams [5 grams per cubic meter per day] to enter; 50 times more than allowable."
(This doesn't make any sense to me. It seems like the diffusion rate would be a function of surface area, not volume of water.)
So at a relatively low temperature you still get about 50 times the oxygen.
Nothing in the doc says what the diffusion rate is per square foot of pex, though. So how does one determine if they are exceeding 0.05 grams per cubic meter of water or not?
Doc goes on to to suggest that systems with lots of steel versus plastic are still good. And, believe it or not, that technically 1500 feet of marginally o2 barrier tubing is above one exchange of system water per year.This post was edited by an admin on October 28, 2013 1:20 AM.
what I got out of this wasYou probably want a boiler that is impervious to rust, or you want an over sized CI unit that can handle a reasonable amount of corrosion spread out over it's surface area. The copper tube boiler I mentioned still has cast iron joining the copper tube segments. Without knowing all the details of its construction, my instinct is that this makes it a poor candidate.
Like CarlSaid the mod/con with SS HX just moved up the list. You don't want any corrosion fouling the system.
A bigger CI boiler only adds more surface area to corrode. You would have to isolate it via a heat exchanger, and that gives another hit to efficiency.
My comment on CI boilers being robust was only intended on longevity compared to a mod/con when properly installed.
I'm sure if you did a search on the wall of non barrier tubing issues there is plenty of ugly on here.This post was edited by an admin on October 28, 2013 5:46 AM.
It seems like the diffusion rate would be a function of surface areaFor a given tubing type (SDR9 PEX, in this case) the ratio of water volume to PEX volume is essentially constant. The larger the pipe diameter, the less surface area per unit of water volume, but the PEX gets proportionally thicker to handle the pressure. Since diffusion is a function of vapor pressure, it's going to track pretty closely.
All it means is it.Buy time before corrosion rears it's ugly head
Ok….The mod con army wins the battle!
This is what I am going to do.
So, now that all other things have been eliminated, is there an ideal way to plumb this kind of setup? I keep seeing this. Why are both the in and out water lines connected side by side to the parallel line the expansion tank is on?
Is this "the" way or is there even better ways to do it?This post was edited by an admin on October 28, 2013 6:50 PM.
anybody wantto buy a slightly used HWT?
Primary secondaryPiping is the diagram.
Basically the primary loop , and the secondary loop are decoupled by the closely spaced t's.
This way the two loops can pump at different flow rates, and not effect one another.
The cadet has a high head heat exchanger which may require a different flow rate than your heating loop.
The primary loop is the loop with the expansion tank. The secondary loop is the loop for the boiler.
Not to confuse you but the boiler loop could be the primary loop if the expansion tank were plumbed in at that loop.
So in a nut she'll most signify the primary loop as which ever loop has the expansion tank.
But yet some signify the primary loop as the boiler loop.
Shooting from the hipRunning a 35* delta on the cadet would be close to the same head loss as .6 gpm on 200' runs of 1/2" pex if the pex is 12" on center that should give you 25 btus a sf.
Can you confirm loop lengths, number of loops, and tube spacing Morpho?
What I'm trying to see is if it is possible to eliminate one pump, and not plumb primary secondary.
If not two bumble bees is still an even swap from your present circ. if we could get it down to one bumble bee it would not make you cringe so much.
You could also buy a small indirect, and make your domestic hot water with the cadet at a higher efficiency than the instantaneous water heater you have.
Got a Craig's list in your neck o the woods?
That makes perfect sense about the primary secondary.
I'll read a bit about it.
The ∆T of 35º…..my understanding was that 10º was "ideal" (of coarse each situation is different I'm sure)
Actual floor space 897
Including under the wall frame 960 (no Pex under the wall)
Total of 911'
12" OC -- 10" in a few key places.
Yup we have craigslist….sort of…The closest main centre is 2.5 hours away where most selling activity is located.This post was edited by an admin on October 28, 2013 8:24 PM.
Delta10* for radiant floors for the heating loop.(primary). 35 at the boiler loop (secondary). The higher the delta at the boiler the more efficiency gained.
10* gives more even floor temps. You could go higher if your willing to sacrifice some foot comfort.
I'm thinking you need primary secondary anyway. Your headloss for the flow rates needed to maintain a 15* delta at the floor( a little sacrifice in comfort under foot) would be borderline bumble bee material. To close to call. Maybe SWEI has a different opinion.This post was edited by an admin on October 28, 2013 8:52 PM.
Ya...The foot comfort is pretty important to my wife. 10º differential is much better.
If this requires a two pumps or slightly less energy efficient ones, so be it. I can make up the power loss elsewhere I guess.
Primary pumpFor that boiler can be one of the little B&G ecocirc e3 Vario pumps (also sold by Laing Thermotech.) You'll have to add a couple of 1/2" union fittings to make them serviceable in a system, but their power draw is nearly nonexistent and the fully adjustable speed control lets you dial in the ∆T you want. You won't get the dynamic ∆T control of a Bumble Bee, but you also won't be forcing the 'Bee to work at or near the bottom of its curve. You'll probably spend about the same as a cast iron 'Bee but a lot less than the stainless one.
this is the layoutif it matters at all
Now I am trying to figure out how to plumb it so this pump comes through the wall in the kitchen because that thing looks cool.
Is this pump going to be a problem because of the non o2 pex?
The electrical numbers look exactly what I need.
Thanks for pointing me to this one.
ecocircis a brass pump, typically used for DHW recirc. No concerns with O2.
WAFFLEI realize the Cadet has a SS HX, but is there anything in that boiler that would prematurely fail in this context?
What killsThat style boilers heat exchanger is mineral deposits from continuous makeup water.
I wish companieswould be smarter about product naming.
It gets confusing.
The ecocirc label seems to cover several models.
The recirc brass pump is the first one I found.
But then I found a model that has the same name, but is different.
I think it's the second one.
ecocirc e-seriesis the one on the left. The smaller of the two will work as a primary pump on the CDL040, assuming your loop has minimal head or (even better) you use a hydraulic separator.
The image on the right is an ecocirc 19-14. It has a cast iron volute and essentially the same curve as the other residential smart circs (Grundfos Alpha, Wilo Stratos, Taco Bumble Bee.)
Just to make it confusing:
B&G sells it as an ecocirc e3-4
Laing sells it as an ecocirc E1
Whatever brand it is, you want the Vario version. Avoid the "UCT with Ball & Check Valve" version for this application or buy the larger model. The additional friction it adds will drop the flow too low on that boiler at high fire.
I *REALLY* wish ITT would offer these in heating trim here in the US.This post was edited by an admin on October 29, 2013 11:10 AM.
Gordy…..that isgreat news, because the likelihood I would be feeding any water into this is nil.
I don't have it to spare!
is there an ideal water to fill the system with? Floor and boiler.
De-mineralized, ph neutral something or other?This post was edited by an admin on October 29, 2013 10:55 AM.
brianBrian I'm sorry.
You wrote a bunch of stuff and I missed it.
Yes there is something to be said for RobG's logic as well..other than I will keep having to do and undo and redo the plumbing and gas lines. I think regardless of what I do I am going to lose….except whatever I do I win. I will have heat. And in this climate f you don't have heat you die. So $600 every 4 years for a tank…or $1200 every 20…or $2500 every 15…it's all pretty cheap in the end considering freezing to death is the alternative. (trying to rationalize spending money is not my forte'. I have to put it into life and death terms)
I see the point you make about the ci boiler being way more robust etc. But there simply isn't room for the boiler and a tank. I measured it out and there just isn't the space. I could add on to the cottage, but combine that with the cost of the ci and the tank and it would probably cost as much as replacing a mod con after 10 years. And after 20 years or so, I'll probably be taking my walker into the woods to go "grizzly bear wrestling" and a new boiler will be the least of my concerns.
The price for propane has been about $1.00 per litre and bulk is currently about $0.49.
I actually did consider the multi 100 tanks idea, but it all starts to become ridiculous after a while and I'm ridiculous enough as is. (tons of stupid things I'm doing right now on top of this. (I'm currently building my own air to air heat exchanger)This post was edited by an admin on October 29, 2013 12:11 PM.
Pretty surethe tank will last longer than 4 years. It has an anode. You don't use it very much. And it's a closed system with comparatively little o2. It certainly isn't rusting from the inside out.
good news for modern morphoit is hard for me to wrap my mind around the idea of space mattering, but that reveals my own predilection and isn't meant to impeach yours. and the mod con is a good choice for space if a compromise on electricity.
if it is of any comfort I do have good news for you i didn't have yesterday.
i just bought a used munchkin (last gen modcon by Heat Transfer Products, was popular entry level modcon also sold as Peerless Pinnacle) from a guy who has installed and serviced several hundred of these units in massachusetts. i, like you, am on propane and he was selling the one in his house (think he just put in a lochinvar actually. his company shifted over after trying weil-mclain and not liking them. so that is an endorsement for the lochinvar product.
but there is more good news. he had some great info from almost a decade servicing these munchkins (which are stainless fire tubes) in both NG and propane use. his experience is that the propane units stay cleaner and don't need the same extent or timing of cleaning as NG. Most of my applications are NG in houses without radiant that operate abouve condensing temps so i don't have that kind of base of experience. i was lucky to be buying this from someone who knew a lot about them and had had so much experience. (also a good reason as you can see to hang out on the wall)
more good news, 50 cents a liter is a damn good price for your consumption level. I pay 50 cents a quart and have three one thousand gallon tanks on the farm and that is the cheapest i can find around here, i shop annually and buy two fills a year.
and thanks for your response to me last note. i have a bad habit of writing novels about this stuff, which is revelatory - vis the fellow who i think was asking not only you but maybe maybe everyone what we got out of this thread - of the extent to which i use the forum to impart ideas, but also to crystalize my own.
I know if i just sent the shortest cleverest quips i could, my 'ratings' would move up and honestly i would help people more because i do have a few reasonable ideas. but i and youse guys are stuck with my loquacious self. i don't write to make you regret your decision but i am often a strong exponent of not giving in to convention. that said, once you came up without barrier tubing and with low temp. coupled with low btu requirements and limited space i can see why the mod con started to seem 'sensible'. I was actually glad to get another unsolicited recommendation for the lochinvar. as you might be able to tell, i live in the land of searchtempest.com (the way to piss craigslist off and search multiple craigslists at once), and buy used equipment. our climate isn't life and death and i keep electric radiators and propane space heaters around to cover breakdowns while i find slightly well used equipment. your location is particularly nettlesome and although there have been plenty of brand new units that manifest problems folks seem to have focused you on a solid entry level unity that is highly recommended. and if you ever do have problems i think you will find a lot of help here (but maybe you want to drain that hot water heater and put it in the cold storage in case you need to grab the pex tools and slam it back in in a hurry some dark winter night - of course I'm not sure where you'd get the 40 gallons to fill it. i guess you melt snow . . .
or maybe you want to keep an eye for a space heater as a back up. there are units that can run with no electricity (spread it a little more if the fan is on but still get eer done even if the power goes out. you can go with a standing pilot and only light it when you're not there, or i think there are even some that have batter ignition or you could put an uniterruptilbe power supply on the ignition (you might have to invade the wiring space and separte the line in to the fan and the ignition so you don't run the power supply down running the fan if you're out of juice). I got some nice 22,000 btu ventless units with standing pilots out of home depot at the end of the season one year for 75 bucks so if you're smarting from mod con investment, keep your eyes peeled.
absolute best of luck and don't be strange . . . eer a stranger
brianThis post was edited by an admin on October 30, 2013 9:12 AM.
I ThinkI still think that the vented space heater is the best way to go.
1. You will never freeze to death if your solar power goes out.
2. You can still use the water heater as your heat source with non-O2 barrier tubing. Remember, a water heater is glass lined to operate using oxygenated domestic water. All you have to add to the existing piping is a bronze pump and mixing valve.
3. It should last as long as any standard water heater and the vented gas room heater will get you through inspection.
4. When smaller mod-cons come out (which they will) you can get one that is properly sized.
5. Back-up heat is a necessity where you live, and the mod-con will break down someday and you might have to wait a few days for parts for a technician
I believe the cadetIs pretty darn close in size by the time you figure the output it's 40k input.
Some kind of back up still is not a bad idea no matter the true heat source though.
Morpho I don't know your water quality, but initial fill of distiller water would be of benefit .
I think the cadetis pretty much the right size as well. Hoping anyway.
My water quality is unknown to me as well. I collect rainwater in a pond and filter it through a biosand filter and into a cistern. I have no indication of mineral deposits on any of the faucets,but I will fill it with distilled, no problem.
I know a guy.This post was edited by an admin on October 29, 2013 10:08 PM.
Stop messing with my head Rob!I still think the tank is a good idea, and as logical and safe as any of the other options.
The cost savings on gas for a boiler are enough to make me crunch the numbers and weigh the positives and the negatives. Then throw in the space savings, the easier acceptance by code and maybe just the fact I just want to put this all behind me and move on.
I have my eye on a little wood stove for backup heat, or maybe I'll rebuild my rocket mass heater…that thing worked great.
I do like the idea of the gas room heater though. I was reading a bit about them last night and they are pretty cool. I'm surprised I haven't seen one before. Had I known about them before I built, I probably would have put one in when I was still flush with cash.
But in the end I need to make a decision and I'm going to try a boiler. And why not?….if it goes sideways…..in the end... whatever… I have wasted money on plenty of things in my day…anybody want to buy a pet rock?….how about a hula hoop?….Ford Pinto?….cheap.This post was edited by an admin on October 29, 2013 9:10 PM.
which worksas long as you keep your loop friction low (which is not particularly difficult for 2.1 GPM.)
loop frictionyou mean no primary/secondary?
Frictionin the primary loop.
how would itgo sideways with friction?
being forced to reduce fittings?
Too many bends?
if the near boiler plumbing turnedinto some kind of elaborate undersized mess, then the head loss thru the boiler and primary loop would be off. As it is (and do read the manual) the quoted head loss typically includes x feet of y diameter primary piping.
wellthere goes my plan to make a mandala pattern!
thenit seems to fit pretty well, with a bit of room for adjustment.
The fittings on the pump are all 1/2" How does going from 3/4" to 1/2" back to 3/4" effect things?
One more question. SWEI…you mentioned a hydraulic separator….is this the same as a low loss header?
Mix the twoLochinvar specifies 3/4" for the primary loop. You'll have to reduce or bush your way to 1/2" at the pump. Look up "equivalent length" to figure your fittings.
Hydraulic Separator = Low Loss Header
Think again about one of those little Rinnai Energy Savers at half the purchase cost of the naked boiler (before any pumps, valves, fittings, or labor.)This post was edited by an admin on October 30, 2013 12:22 AM.
How would a "wall furnace"make the bare concrete feel?
Man Alive!Now even SWEI is telling me to ditch the boiler!
Informed decisionsAre unfortunately rare in the world of residential and small commercial HVAC in North America. I really wish that were not the case, but the combination of clueless contractors and unnaturally cheap natural gas has distorted things pretty severely of late.
Apologies for the surfeit of theories and proposed solutions here. Most of us are quite practical when it gets to decision time, but there is a LOT of information backing up those decisions. If you ask us to explain, we generally oblige -- often missing the "eyes glazing over" cue which would be obvious if we were all in the same room.
I'm going to guess that the CDL040 and associated hardware is going to cost you at least 3X what one of those modulating Rinnai Space Savers would, exclusive of labor. As Eastman points out below, the simple payback on this flat out sucks. This doesn't mean you shouldn't do it -- we see customers all the time who want the comfort of radiant floor heating and (within limits) don't care about the cost, the same way they want certain windows, doors, wall finishes, or countertops.This post was edited by an admin on October 30, 2013 10:16 AM.
How much..I'll take the hula hoop.
No thanks on the rock and the pinto.
This has been a great thread, thank you.
It is unusual when what is usually the worst design (water heater) is actually the best option.
Sorry about the code.
the hoop is yoursI'll throw in the pinto…brown with brown rust accents.
The hula hoop and the pinto when combined are a total chick magnet.
glad you find the thread funI am to please.
I think the people posting here are amazing actually.
Not a single poster on here was anything less than genuine in trying to offer advice about what might work and have been unbelievably monk like with all my dumb questions.
the delta T and steam threads are the bestFor what it's worth, I also wouldn't be quick to launch into this project. The biggest issue seems to be the price your paying for fuel. If we take your 400 dollar bulk propane annual cost estimate at face value, how much more could you really save with a modcon? Even if the space heating efficiency doubles, (which it very well could) what are you saving after you factor in your other gas appliances? --170 a year abouts? That's about a fifteen year minimum payback with additional capital risk.
I don't want to encourage you or anyone to violate Canadian codes, but certainly you should be aware that the best choice is not necessarily the right choice.
eastmanIf his only choice is LP why not? Wood Looked pretty distant on the property.
Oil is going to be more than LP.
Dont over think it.
it's all bad news.There is no win in this situation.
Here in Canadastan, the certified tank costs a little more than half the cadet price and the ci comes close to the cadet number. And in my opinion they are all pricey…not that they are over priced…I'm just a cheap S.O.B…..but in the end I need heat.
The propane cost of 400 is only for heat, the cadet should, in theory, shave off, lets say 30%.
$1440 over a lifespan of lets say 12 years. And if Marks experience holds true a once every two year service on the unit will keep it in good working order, well that pretty much balances out the Lp savings..they go into the maintenance.
So, the difference between the lowest capital cost and the highest is basically for comfort, space and code acceptance ….divided by 12 years.
Good points on the payback vs desires. i.e.: fancy countertops etc.
I built this place simple and efficient and by myself and saved a whack of cash doing it. I didn't put in granite countertops etc. (is there a payback period on granite?) but I did put money into good quality windows, stove, etc. Things that would benefit our existence and comfort…. in my opinion anyway….for some granite is worth it….me?…I put it into solar...That saved me money in a big way.
The payback on that was day one because the PV system cost me about the same amount as the power company wanted for a single pole and a transformer. (did not include getting the power to the house)
Its not wholly about money. of course I want to spend as little as possible, but there is no getting away without paying something to someone. So then what is it about? Saving the spotted tree whale? I have so much eco cred banked up I can hunt those suckers into extinction and still be good. Comfort?….I am hoping I can see a bit of upturn in comfort.
Space…oh yes space would be great. Every time I go into that room to do something it is a gymnastics routine waiting to go wrong. Though the sparkly spandex outfit looks great on me! ;)
So what will old Morpho do?….hmmm?
I don't know…I'm waiting on a quote for a cadet…things here in canada can…for unknown reasons….be priced way over what you folks see on the tag down there.
But I know a guy who is building a whole subdivision, so maybe he can get it at a good price for us.
oil!?oh man…i don't think i know anybody with oil heat….just doesn't exist out here.
There is a guy a few sections over who has a coal fired boiler…huge thing with a massive hopper.
The NG is about a km away from me, so not likely to get to me any time soon.
Lp is pretty much my only easy option.
think eastman was talkning modcon cost benefit , not fuel choiceI don't think eastman was saying look at other fuels. he was going to the payback form the investment to qualify for bulk delivery.
don't know if you noticed up thread but morpho did reply to my question about propane unit cost involved in these calculations.
he was t about a buck a litre and could get it bulk for 50¢ a litre. that's a pretty steep discount. i'm sure he could split the difference with larger self serve tanks and filling more of them at once, but i got the sense he had considered that and figured that there was an opportunity cost to him assembling a fleet of 100 lbs tanks and undertaking to transport them.
and of course i don't know if he has a car or truck so how many of those he could actually carry before rosco p. coltrane shuts him down etc.
so i think the point was it was $800 a year the way he is doing it and would go down to $400 a year delivered. You figure you could forward commit 5 years of that difference if you acceptin the first place (which i don't*) that there is any decent reason why the inspector should be worried that some guy in the middle of nowhere off the grid wants to use an 'uncertified' hot water heater.
Now i think the $300 maintenance allowance people talk about for modcon would eat that up, but i think that is related to the cost of a serviceman cleaning the boiler and not what you'd expect to spend if you maintain it. Don't know about the servicability and access for cleaning on these lochinvars but i was pleasantly surprised to hear from a long time munchkin installer and serviceman who i met this week that units in propane service are much cleaner and require less frequent prophylactic service. Since even at 50¢ a liter we're paying going on twice as much per btu compared to natural gas around here it is nice to know that we make out it one respect.
*Nobody said the install is unsafe. This certification thing stinks to me like Food and Drug Administration screwing up drug approval processes by not focusing on whether a drug is safe but on trials proving its efficacy for labeled uses. i understand you can even make a case for having some independent , gov. or otherwise, kind of underwriters laboratory stamp of the appropriateness of a product for certain uses. But the comingling of govt. regulation against the products use for off label with its safety regulations is a bad precedent.
So without the UL label you can't be disappointed if the thing doesn't last as long as you were hoping and maybe you can't make a warranty claim for a new tank if you have had it in heating service. so, if you go into that knowingly, WTF is the problem (i try not to use acronyms as i know i can get left behind when i don't know the latest ones, but i trust it is more polite in this case.)
Honestly, whether with the hot water heater system or the mod-con i would think an outbacker like morpho would do well to have a space heater back-up that uses no electricity anyway.
my 2¢ -- well as usual it looks a little more like my 50¢
geez the friggin math questions to post are getting hard. i had to take off my shoes. i still can't figure out why we need that if folks have an ID and are signed in but guess there isn't too much spam here , if you don't count my posts that is, so maybe it is important
Yup…no truck.Just a little hatchback…which I have hauled an amazing amount of crap in over the years…100lb lp tanks included….but my back isn't what it used to be…so I opted for 40's.
The power around here has gone down a lot…usually from oil and gas development….big machines knocking down lines. I usually just giggle to myself. But I'm sure something will come my way one day and I will need to fix something or other. When I first built the place and still had no heat up and running the passive solar was keeping it… if not comfortable…at least well above freezing. How would it perform on a long stretch with no sun in -22º…probably not well for not long…so I will put in a wood stove next spring. I have about 4 cords sitting in the back 40 that the power company dropped off when they were clearing for lines in the area.
This way I am independent of LP and Power if that goes down for any reason
Just for the recordthose little Energy Savers are NOT the same as a typical direct-vent wall furnace. They are modulating miniature comfort machines. Really.
so SWEI[t]yeah, as to space heating -- it depends. the 22,000 i bought is made to mount on the wall or free stand has standing pilot no vent and normally retails around $275 or $300 bucks i think.
if i were thinking longterm backup might think about a small vented model, but i was sensitive to the money it looks like he is about to expend. ironically, if he bought the back up and installed it and ignored the hot water heater, maybe he could get his delivery service and then get the hot water heater going . . .
i'm not trying to make him reverse field and i think sometimes when you've taken a decision you don't want to be second guessing yourself the whole way but his situation seems to beg for some no electricity needed backup.
bulk LPMaybe I missed something, but why is bulk LP delivery an issue? You have to pass some kind of inspection to get LP? Can not the tank heater issue and LP issue be resolved independently?
LPGYa, so the Lp guy's need an approved installation before they can fill up the tank.
Fair enough...liability I guess…
SynopsisSynopsis is heat source in code violation, so no bulk propane hook up for you until resolved.
So Morpho I was going to ask what the pros/cons of doing nothing about your situation?
No out of pocket to rectify violation of heat source.
No final occupancy permit?
No bulk delivery of propane.
Fines imposed possibly?
Is there a time line inspector is enforcing?
The problemboils down to:
-no LP hook-up
-in violation of the code, so they could make a dogs breakfast of my life if they wanted to...fines are a possibility, but I don't know for sure.
And it's not my intention to be under board about any of it...that's not been my intention. I want it done right and safe.
-I have occupancy so that's not a problem.
I have about 8 months to do the work and have it inspected. So not a massive rush...but sooner than later is always a good thing in my book.
So actuallyYou could get through another Canadian winter.
Devote spring /summer to an installation at your leisurely pace. Time to squire products. Maybe monitor your present system a little closer record readings, and compare to new installation.
what modeltakagi do you have?
UUUGHH!Okay, so I got the quote back from my buddy on the cadet.
It may be little, and it may have a cute little name…
But the wholesale price he can get it for me for is…well….lets just say….
You know the 30% less than other units that was thrown around?
Well, here in Canada (god I hate this place sometimes) ADD 30% more onto the price of a Lochinvar 44k BTU knight in the USA…. thats what I'm looking at.
AND THATS WHOLESALE!
The tankless I have isn't a takagi…I was looking at them for the floor heat.
I have a Rheem for DHW…which is a rebadged Paloma in reality.
Okay, so now I need to rethink my whole life.
specsI was just wondering what qualities the tankless had that is working well for you. Perhaps there is a combi boiler that could match those specs, then you could sell your current unit which is pretty easy to ship.This post was edited by an admin on November 2, 2013 2:07 PM.
MorphoSorry to hear that. Price other brands see what you get.
sticker shockpexsupply.com $2548 for 44K knight
don't know what you were getting. but i bet they would ship to canada, and you're looking out 6 months. . . I don't think that is a particularly attractive price for a boiler, but i'm a stick in the mud and they are usually pretty good on price. what were you running into up there?
you know that my view is get a space heater for a backup, get it approved, get your bulk propane and then go back to the hot water heater for the warm floor.
bhvfnoasiubdnvafoivthat was my head hitting the keyboard.
The tankless has been great for space and the endless hot water….or at least the idea that if I had endless water i would have endless hot water. Though this is the first time in my life I haven't had to suffer through a poorly sized HWT for domestic use. The two litres of cold water I have to run before it gets hot isn't an issue. I have a little bucket in the shower, so I don't actually waste it. It goes to the dog dish or water plants etc.
So yes I have considered selling it and putting in a combo…
Ya tell me about it!
I worked out the difference between the US price and here….49% higher for the Cadet ….Thats crazy….We get shafted so badly here. We make cars here then ship em down to the states. Nothing is different…same car…but we pay thousands more.
I doubt it will make much of a difference between manufacturers.
The dual purpose DHW tanks are pretty much the same…if it's 800 in the US…well here it's 1500. That crazy Vertex AOSMITH condensing HWT came to somewhere around 5 grand….ooops…sorry…not supposed to talk actual prices.
Even the wall furnace is going to be a wad of cash.
Yup, thats the one I based my pricing difference off of for the Loch Cadet. The little booger is 30% more than that one.
Hell, CI boilers here start in the 2 grand area.
I am waiting on a price from Pex supply….they don't carry it yet.
I could fly down and buy it,…have a vacation…fly back and still come out ahead.
Okay, I have to get back to working…..
Have a good one everyone.This post was edited by an admin on November 2, 2013 10:19 PM.
Hate to be the bearer of bad newsBut according to their shipping policy, pexsupply doesn't ship outside of the U.S. I'm pretty sure that includes us up here in the Great White North.
so he has to have someone in the state's he trusts not to sell it on craigslist. . . I'm not saying that is me but aren't any of you other guys trustworthy.
don't know why someone wouldn't ship to canada -- maybe the shipping wouldn't be free but. are we having a trade war? WTF.
I think they do ship.... Or they didTo Canada but who knows.
Don't sweat my shipping guys.... I know a guy in so-cal that ships stuff all over the world for his business. Actually that's how I got the tankless.... now that I think about it.
Thanks though.... Cool that anybody would even think about my first world woes.This post was edited by an admin on November 2, 2013 11:06 PM.
NFN back to takagii'm going to call Takagi on Monday, just because inquiring minds want to know.
Various Amazon lisitings say the Jr. is good for Radiant heat according to the manufacturer.
so all you have to do is get your inspector to go to amazon.com. well alright that might not work but even moving up to an T-H which is their condensing model and says on the Takagi site it is rated for heating is going to be half the price of the knight.
e.g. Tk JR already set up propane for $576
but look the T-H is only $1276
both of those are prime so i'd get them in 2 days for free shipping. don't know what the deal with canada is but both say "This item is also available for shipping to select countries outside the U.S." Don't know if Canada is a 'select' country but since they can ship us oil, hydroelectricty, etc., i'd think we could ship a couple 50 lbs. boilers up there. if anybody has got it worked out Jeff Bezos
probably does (if he's not busy in davos or somewhere).
and the takagi's are small and hang on the wall so you would have space for a transfer tank to isolate the tubing, although i think the heat exhanger is probably close to as resilient as stainless steel, but i believe they use copper, like the heatmakers. i always like that myself. you could melt the heat exchanger with no flow, but they got their flow safeties worked out and it was off to the races.
i'll get back to you with whatever takagi tells me about 'certification' for heating applications.
inspectorI think the problem from the inspector's point of view is that morpho has gone out of the grey and into the black. He took an appliance and exclusively re-purposed it for a situation it was not designed for. If the tank was restored to open loop DHW, and heat was delivered via something like a taco xpb-1, is not the problem resolved? It seems like installing a tankless water heater in closed loop operation would be likely to recreate the original complaint.This post was edited by an admin on November 3, 2013 12:24 PM.
takagi literatures says they are for radiant heating as wellIt says that in some places on some models but there it isn't easy to figure out if they just mean the is a suitable off label use or if some fo them have 'certifications' to go with. It doesn't say anythingspecific about that in the specifications on their web site. They have a bunch of glyphics for their certifications, but they don't have a text version that tells you what the glyphics mean. some have initials that might be recognized here, but i don't know why they don't just spell it out.
i'm gonna call 'em up and find out what they say about this
Forget the tanklessSeriously!
Brian your research should lead you to the wall tankless WH are not boilers. Use the right tool for the job. Enough said.
Look closely at the warranty for closed loop heating , and that should be enough to note they are not designed for that purpose.
The taco xblock would work IF he ditched the tankless, and converted the tank style WH for domestic use.
Now the xblock is expensive, and I believe the tank WH is a little short on output. Using a HX will make it come up even more short on output due to efficiency loss of the xblock.
I think the biggest problemwith the xbloc in this situation is the electrical usage. Certainly a much better version could be made if one rolled their own.
tanklessEastman, Gordy, Brian:
Yup, the xbloc would solve the problem and create more as mentioned.
The tankless from Takagi would pass code as long as it was the ASME H version. TM-32, TM-50
Though I am unclear whether the "ASME H" means it okay as a stand alone or I would be back to having to use it as dual purpose. I've yet to get an answer what the "dual purpose designation" actually is.
It is really confusing to have a certification that says it's for heating…but then come across a common opinion that it isn't really for space heating. Why would the ASME folks certify it if it's not really for that purpose? Then you have to wonder why I should trust the boiler…it's certified ASME as well.
Okay, a bit of a stretch I know…but you know what I mean.
This has all become wacky….
If I can get my hands on the cadet for a reasonable price I'll get it.
If not, I'll get a….a…well, I don't know….
The takagi is"HLW" Lined potable water heater not "H" cast iron heating boiler
So there you go….it would have to be used as a dual purpose.
finally got an answer from Takagi engineeringwhich is essentially as Morpho expected, but clearly shows the company standing behind the use of all its units, HLW certified and not, for heating use but recognizing the realities of local decisions. You'll notice that in practice Takagi has seen some jurisdictions allow dual use, but not that it is required. And the engineers reference to the difference between H and HLW requirements suggests again that there is no evidence whatsoever the HLW appliances are not appropriate for low to modest temperature applications with observation of necessary overtemp, flow and water 'level safeties. It seems it would behoove the industry to develop a best practices set of standards for those kind of uses for non "H" stamped appliances. As to whether the HLW itself is even required that would seem an open question from Takagi's point of view -- jurisdiction specific but not anything they shrink from.
I apologize for how long this has taken for a response. I have looked into this. There is a difference between HLW and H stamps. As you noted HLW is for potable use and H is for heating. There are differences in testing standards between the H and HLW standards. I believe the H stamp is more strict because it is dealing with higher temperature water and potential higher pressure issues due to most heating systems being closed loops. HLW is for potable use so it is unlikely that water temperatures will go above 180 degrees where a heating boiler can go up to 210 degrees.
Every jurisdiction is different as to what codes they adopt and follow. In most locations in the US the inspectors do not enforce an H stamp requirement for heating applications. That is why we state that our heaters can be used in the applications. Application wise, our heaters are very good for heating systems. It is the administrative side that makes it tough.
I have heard where inspectors will allow dual use with the HLW stamp, however, that is a locale issue and you should check with your local code officials.
If they are going to require an H stamp product for your application then I have to tell you that we do not produce a product with the H stamp.
I hope this information was helpful.
Tankless Application Engineer
As I have mentioned previouslyit is possible to make these work well in a heating application, but by the time you spend the money to do so, a mod/con will usually end up costing less (and occupying less than half the floor space.)