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Time to choose a boiler (52 Posts)
Time to choose a boilerKnowing very little, I googled for a new boiler recommendation and I wasn't satisfied with the information I was finding, somehow I wound up here. I'm building new construction (2,800 sq. ft) on Long Island and I'm using radiant heating throughout, with white oak floors. I'm going with a direct vent boiler (no chimney) and separate hot water holding tank. My contractor recommends the slant fin Lynx but I wanted to verify if this is a good unit or if I could do better. I have read about Buderus, Triangle tube, Veissman, Peerless and others but getting mixed information. I know proper installation is key and want to make sure all the extra "peripheral" parts are installed that some installers or contractors may leave off to save money. My desires are probably like most, energy efficient, quiet, reliable, and easy to maintain and get serviced. BTW, I'm using LP gas so It's easier to convert to natural gas when it eventually (hopefully) gets extended from down the street. So with that said, and assuming I gave enough info, what would be a good choice?
Unlike most consumer itemsthat don't require highly skilled installation,brand takes a back seat to the installer. We are on LI,I prefer Viessmann and Tringle TubeThis post was edited by an admin on May 8, 2013 8:44 AM.
Firetube HXI would go with the triangle tube. The firetube exchanger is stainless, has less maintenance and takes less circulator energy. They also have excellent tech support .
The slant fin and buderous are aluminum. Aluminum is a bad choice for a boiler.
Most of the other players use a giovanni heat exchanger. High maintenance and finicky.
Viesmann is also a fine product.
KnightDon't forget lochinvar knight fire tube boiler also .
You have choices of quality products. Use the one that fits the heatloss as close as possible, but yet is in supply in your area for parts, and service.
Aluminum block boilers are a little more finicky on water quality. Some people have no problems while others do. So water chemistry is something to look at regardless. There are additives for poor water quality by Rohmar.
You already know the key is installation this site has find a contractor search.
Make sure those white oak floors get acclimated to your homes conditions before installation 10-14 days.
What type of RFH are you doing?This post was edited by an admin on May 9, 2013 6:23 AM.
Time to choose a boilerThe reviews I'm finding on the internet are almost useless, even brands that come highly recommended get their share of bad reviews. Some possibly due to bad installations, some have a hard time getting parts, some have premature failures, noises, leaks, seems warranty and ease of service are more important that I originally thought, slant fin is starting to look better for my long island NY area..... many of the so called better brands seems to have worse warranties, pretty odd.
I also would like to understand the difference between a sealed combustion boiler and a modulating condenser boiler.
As far as what type of RFH, not sure what your asking, as far as I know it's just PEX laid in a sort of 5/8" MDF board with grooves cut in, I assume closed loop, been told I should get factory made manifolds and not "home made" manifolds made by the plumber, not even sure what that means.This post was edited by an admin on May 9, 2013 7:34 AM.
Slant/Fin is a great companybut the Lynx has an aluminum heat exchanger which would not be my first choice for a condensing boiler.
Time to choose a boilerOk so it seems stainless steel heat exchangers are preferred over aluminum so would this be a better choice than the lynx?
Slant/Fin CHSThe CHS is a new line and I have no experience with them yet. Drawings in the IOM look similar to the vertical firetube design TT pioneered, but the HX flow restriction curves are quite a bit higher (though still far less restrictive than a GIannoni.) Anyone know more?
Note that the smallest size they offer fires at 85k. Minimum turndown is 17k, essentially the same as the PTS 60.
Time to choose a boilerThis is the other option offered by slant fin:
Modulating condensing boilerIs a boiler that modulates its output according to demand for heating. Usually a 5:1 turn down .
A closed combustion unit gets its combustion air from outside the home. It has one output rating. So when you need heat on say a warmer day you will get full output verses a modulating boiler which can ramp down to the demand closer.
There are various types of radiant floor assemblies.
Pex poured in concrete.
Pex poured in gypcrete.
Sandwich which is as you are describing.
Staple up which is pex attached to the bottom of subfloor.
Suspended tube in which pex is attached to the floor joists underneath the sub floor.
Are they using a prefab panel system that has an aluminum layer attached to the face?
Or are they using heat transfer plates?
What centers is the tubing layout.
Educating yourself to make a well informed boiler choice is good, but there are choices to be made beyond the boiler at the emitter end that will make your system more efficient. The lower water temps you can run with a modulating condensing boiler the more efficient it is. This means using plates to conduct the heat to the floor thus lowering supply temps, and or increasing the floor output.
Rule number one is a room by room heatloss if your installer is not doing this don't use them. This IS a science not a guess or rule of thumb to produce the most efficient system possible.
Re: boiler choiceGo with Triangle tube PT boiler. Great stainless vertical firetube condensing boiler, also you can drive to the factory in Blackwood NJ if something goes wrong :) . The Lochinvar WHN boiler is very similar, basically the same heat exchanger design with their own control. Triangle was the first in this size range of boiler that had the vertical firetube and has been a great performer. have over 60 of them installed over last 7 yrs and very happy overall. Not to say nothing ever fails on them but overall solid.
Time to choose a boiler"Sandwich which is as you are describing."
Yes I'm pretty sure it will use something like this:
I also made sure the contractor uses white oak as I heard it's more stable with radiant heat than red oak.
I told him I want a layer of some sort of fiber paper between the sandwich layers to help prevent wood on wood contact to prevent squeaks, I'm also going to make sure he uses screws. If there's any other advice on that I'm all ears.
"Educating yourself to make a well informed boiler choice is good, but
there are choices to be made beyond the boiler at the emitter end that
will make your system more efficient. The lower water temps you can run
with a modulating condensing boiler the more efficient it is. This
means using plates to conduct the heat to the floor thus lowering supply
temps, and or increasing the floor output."
Do they make a prefab radiant heat panel like I posted above with some sort of foil built in? Is that what you mean? If so I couldn't find anything.
"Rule number one is a room by room heatloss if your installer is not
doing this don't use them. This IS a science not a guess or rule of
thumb to produce the most efficient system possible."
I'm taking notes!! I am going to make sure the installer goes by the manual. I posted a link to the slant fin CHS over the LYNX as I', told stainless heat exchangers are better then aluminum. I am leaning towards slant fin as they are Long Island based, have a very good reputation for helping when problems arise, easy to get parts and a good warranty ( 5 years). Although there are others that seem like good boilers, ( triangle for example was mentioned), but I'm open to suggestions. I have to admit I know very little about this stuff but appreciate the help I'm getting here.This post was edited by an admin on May 10, 2013 7:10 AM.
Conductive Heat transferIs king that means aluminum heat transfer plates, or a Roth panel, warm board is another.
We are not talking foil. But stamped aluminum there are light weight, and heavy gauge plates heavy gauge is better.
Heat transfer plates keep water temps lower, and spread the heat more evenly across the floor plane. With out them stripping is more noticeable .
The CH 160 all though ss hx is probably to much boiler 160000btus . But with out a heat loss calc you don't know yet.
Heat lossAs said before.
Absolutely a heat loss is needed.
You need some means of dispersing the heat whether it is a slab or heat transfer plates.
As for the boiler. I would look at the type of exchanger. Also look at the company. Are the a copper fin or cast iron company that also does condensing boilers. Or do they specialize in condensing.
CarlThis post was edited by an admin on May 10, 2013 11:13 PM.
ChecklistThanks for the responses and putting up with my ignorance on these things but I'm trying to learn enough to ensure I get a good installation job and cover my bases.
Radiant heating: ( new construction, LP gas, white oak wood floors )
Ok so now I realize I didn't put enough thought into the sandwich material, have come across thermalboard, quicktrack, warmboard, & heatply. From what I'm gathering the metal spreads the heat more evenly, retains the warmth better and you can space the tubing out more. I would like to use plywood and construction adhesive and screw it down to help prevent squeaks. I don't know how expensive this stuff is and cost is definitely a factor, At 52 years old I hope to be in the house 25 years as recoup time but that's obviously a guess. Any input? anything else I'm missing on the radiant heating? Anything about the manifolds?
Checklist for Boiler/Installation
Find qualified installer
Do heat loss analysis for proper boiler sizing
choose boiler with good warranty, easy to find parts, good technical support
Stainless steel heat exchanger over aluminum
Read installation manual and require installer to install as per specs
Must have digital combustion analyzer
Set up/tweak low & high fire CO2 specs-verify specs
ad surge protector breaker for boiler
Is super store OK for the indirect HW holding tank?
Anything I'm missing? Of course boiler recommendations are helpful? I'm on Long Island so manufacturer and parts availability are one of the reasons I'm leaning towards Slant Fin's CHS, http://www.slantfin.com/index.php/products/boilers-residential/chs They seem to have a good reputation for customer service and a good warranty but open to suggestions.This post was edited by an admin on May 11, 2013 8:41 AM.
ChecklistFind qualified installer Absolutely
Do heat loss analysis for proper boiler sizing Yes, Heat loss will also help you determine the tube spacing and how many plates you need in each room Not all rooms will have the same loss. Not all rooms need the same amount of radiation.
choose boiler with good warranty, easy to find parts, good technical support Not sure how slant fin made the list, how long has that exchanger been in the field? A good warranty is one thing. Knowing you will never need it.... Priceless.
Stainless steel heat exchanger over aluminum. Yes Firetube over Giovanni also
Read installation manual and require installer to install as per specs Yes
Must have digital combustion analyzer Yes
Set up/tweak low & high fire CO2 specs-verify specs YES
ad surge protector breaker for boiler Depends, The TT trimax has that covered. I watched a demo where they turned it down to 80 volts and it still ran perfectly.
Is super store OK for the indirect HW holding tank? That is a good one, Heatflo is also nice.
Anything I'm missing? The function of the aluminum plates is that they tranfer the heat to the floor faster. This allows the the boiler to run at lower temps and much more efficiently (because it is condensing). Make sure you get the right tubing. Pex-al-pex is nice for your application. Any Pex-a product will also work well. An O2 barrier is a must
Double check the propane conversion. Some boiler are more difficult than others. If memory serves me, The tt110 can be converted from propane to Nat. gas but not the other way. There are a few anomalies out there so double check when in doubt.
checklistNow I need to find out how much more the radiant heat sub floor with aluminum costs to purchase as compared to without aluminum and I suppose the return on investment.
One other question that comes to mind, I'll assume you don't want to run the RFH under kitchen cabinets, the island, things like that? Probably the same for vanity's in the bathrooms.
Any other brand name boilers with good warranties, good support, easy to get parts, S.S heat exchangers ( firetube of course:) I should check other than Slant Fin ?
Anything I should know about the manifolds? Anything else I'm overlooking? Thanx for educating me on these things, hopefully I don't scare the boiler installer away:)
ChecklistDesign is critical, and one of the most important aspects is the efficiency of the distribution and emitters. If you can build a system which meets your winter needs using water supplied at ~120F or less you will gain access to a world of comfort and efficiency about which others can merely dream.
Hire a good designer, who may or may not be a contractor.
Emitter placementNo tubing under cabinets.
Remember if you price warm board the panels are structural meaning you will not use conventional plywood sub floor. The warm board goes down right on the joists. So deduct the cost of plywood that you would normally use from the price of the warm board. If you are already past that phase warm board makes a warm board r that goes on top of existing sub floor.
If areas need more output than a radiant floor can provide consider radiant ceilings instead, or in addition to.
Firetube HXI would consider triangle tube or lochinvar.
It doesn't make much sense to put heat under cabinets.
Once you get a heat loss number per room, figure out how much tubing and plates you need per room.
As far as manifolds go, If you design your system right with careful balancing and equal loops, You should be able to go with a simple manufactured copper manifold. You can buy a manifold with gauges and valves, they cost more but are not needed if you do it right.
I would be picking a good installerand let them pick the boiler, you can give them a recommendation like v-man or Triangle tube, but make sure you get someone you are comfortable with.. thats first.. There area few fine techs on here from LI, Robert has pics of his work, Im sure you will be satisfied..
final checklist?Ok I think I have my checklist finalized thanks to all your help and I
feel I know a lot more than before I came here:). Z-man mentioned this but I am not sure what an
02 barrier is if someone can explain that? I'm still checking into the type of grooved flooring to use ( thermal board-quick track-warm board-heatply ) but I already have a 3/4" sub-floor installed so this will go on top of that, then finished off with oak. I have to decide about the heat plates and not sure how to space them until a heat loss analysis is done? I also know I want to screw it down and use construction adhesive.
Here's my checklist for final approval:)
Find qualified installer!!!
choose boiler with good warranty, easy to find
parts, good technical support
Installer should do heat loss analysis to determine
BTU size of boiler, pex spacing etc
(Not all rooms will have the same loss. Not all
rooms need the same amount of radiation)
Installer should have digital combustion analyzer
Installed as per manufacturers specs from
installation manuals and documentation
Set up/tweak low & high fire CO2 specs-verify
boiler should have stainless steel heat exchanger
over aluminum. Firetube being better than Giovanni
design system to run on hot water supplied at ~120F
no radiant tubing ran under cabinets
manufactured copper manifold: design the system
with careful balancing and equal loops.
Indirect hot water holding tank: Superstore or
Tubing centersRemember the goal is to try and get supply temps 120 or lower. So to do that you may have to tighten up tube centers to achieve that goal in higher loss areas. Generally in baths, and high traffic bare foot areas 6- 8 inch centers is nice. No more than 12" in a low loss room. Plates plates heavy gauge.
You can make your own sandwich detail with 1/2" plywood rips, and heavy gauge plates.
O2 barrier tubing does not allow o2 diffusion through the tube wall. Non o2 barrier tubing allows o2 in the system which will create havoc with ferrous system components. So do not let anyone slip you non barrier tubing.
checklistO2 barrier tubing does not allow o2 diffusion through the tube wall. Non
o2 barrier tubing allows o2 in the system which will create havoc with
ferrous system components. So do not let anyone slip you non barrier
Thanks Gordy, I'll ad that to my list, I assume you mean the pex tubing for the floor?
You got itNow for the fun part. About 95% of the installers will look at you like you are nuts. First the head will turn to the side like a curious puppy. They will then start explaining how long they have been doing it their way.
The guy you are looking for will get a huge smile on his face and tell you how much he likes an informed customer.
Another reason he will smileIs he knows that you will be demanding specifics for a system, and he stands a better chance to do the work for you because. Your not just generalizing I want radiant heat.
He knows now that he's not going to be competing against some hack that will be the cheapest bidder, because the other guy did not do a heat loss, is maybe going to use non barrier tube, no plates, the cheapest boiler, piped marginally right. And will not be found if things do not turn out as you expected.
If you find three bidders that are going to bid the work to your specs they should be reasonably close in dollars. Not thousands of dollars different from a, to b to c. If they are you need to find out why specifically. Don't right off the most expensive bid he may be doing something better than the other 2 guys.
checklistI'm used to 95% of them looking at me like I'm nuts:) but i'll keep trying to do my homework anyway! When they tell me to trust them, my knees get weak, when they tell me not to worry, I start to worry:).
One other thought came to mind, Don't I need to get the heat loos analysis before they choose the radiant heat panels? If I understand what you guys are saying, the heat loss analysis is what will determine the spacing of the tubes and not all rooms will have the same spacing ? So i assume the manufacturers of the radiant heat panels make the grooves in different increments? Just trying to understand that part.
Tube spacingYes you are correct . Heat analysis first. Otherwise you have no idea what load your dealing with in each room. The load dictates tube spacing, water temps, and flow rates to the loops of the panel in a particular room.
Tube spacingOK, so that seems to complicate things, I don't think the floor panel manufacturers give you the option for spacing. Warmboard for instance, only spaces them out at 12", many others 8" , how are you supposed to choose a brand of floorboard when your spacing may not coincide?
It depends on the performace of the boardSome dry systems (generally those with more aluminum) are more efficient than others. Design will dictate what water temperature and how much floor area gets tubing in which rooms.
QuestionsThe Radiant Flooring Guide answers all of your questions in great detail. It used to be available as a pdf download but I couldn't find a free link.
Here's a link:
http://www.radiantprofessionalsalliance.org/Pages/RadiantFlooringGuide.aspxThis post was edited by an admin on May 16, 2013 10:53 AM.
These are the panels the contractor would use if I don't spec out something different. 5/8 fiberboard with foil, 8" spread, glued and screwed down to underflooring. The nails for the oak flooring will be long enough to go through the MDF and into the 3/4" subfloor. Think I'll be OK with these panels?
Panels and heat spreadIf you look at how WB, and plates wrap the tubing it's easy to understand their performance.
I don't know how you can get much heat transfer from the tubing to the panel with out the aluminum in the channel. Why bother with the aluminum layer if it will have little or no contact with the tubing?
It appears the zurn panels aluminum layer tucks into the edge of the groove, and not the whole channel. A missed btu transfer opportunity.
This is why WB can have a standard 12" on center panel. It can transfer more heat from the tubing to the panel, and spread it out. This saves money in tubing, and labor to install it.
The gauge of aluminum is also a big factor in plated sandwich or panel systems.This post was edited by an admin on May 16, 2013 10:54 PM.
MDF radiant panelsNot a great choice, in fact the National Wood Flooring Assoc. doesn't even approve of MDF and it will void any manufacturers warranties. They only approve of OSB or plywood. I plan on explaining to my GC that I have a huge problem with him attempting to use a material that is not approved and will void my warranty but I suspect he will tell me that he does it all the time and the NWFA is just some B.S organization.
Back to the panels, At this point I check out all the major players and concluded what I don't like:
Heatply- plywood but no aluminum
Zurn- MDF, nuff said
Thermal board ( maybe thermboard bros) - see above
Roth- styrofoam and very overpriced
Quick track- small 5/16" tubing, metal backing on bottom of plywood
Warmboard seems to be the winner BUT very expensive at $7.35 SQ ft, at 1,500 square feet that's $11K - $12K, out of my league.
I'm researching another alternative using 5/8" plywood and aluminum, will check back when I get a sample.
BTW, 02 barrier tubing is a must and will void the warranty on the boiler so my contractor has to use it, I wonder if there's an easy way to check to verify that? Probably written on the tubing ?
Lastly, the boiler, the Slant Fin CHS is probably what I'm going with over the LYNX. it has the stainless steel heat exchanger you guys recommended and it also uses the Firetube not the Giavanni and it's only a few hundred dollars more than the LYNX which is what the contractor offered. Hope I'm being a good student, thanks all for your help!
P.S, The Energy Star guy did something called a manual J, is this used for the heat loss analysis?This post was edited by an admin on May 18, 2013 9:06 AM.
Manual jYes that's a heat load.
When you get the results you will know if the S/F CHS model is to big. I suspect it will be. Over sizing the boiler is no good either. 120,000 btus is a lot.
GC saying he does it all the time with wood floors. Just tell him he's done it wrong all the time then. You have educated yourself.
Warm board r should be cheaper. It's designed to be over existing sub floor hence the r for remodel. You get what you pay for.
You can build your own sandwich floor. With 1/2" plywood rips, and plates. This also allows you infinite selection of tube centers. 6" being the narrowest with 3/8" pex.
tube I.D.The approvals for the tubing should be stamped on it at some point. DIN 4726 is one it should have. It's a German standard used to measure oxygen permeance in pex tubing.
Chose the radiant panelsWent with Sunboard panels from North East Hydronics: http://www.sunboardpanel.com/
I chose the 3/4" plywood with 1/2" tubing on 8" centers, hope you guys approve. The warmboard was just too expensive and this seemed a good alternative. They are also a local company and very close to my project, they also help design the system, amount of loops, manifolds, heat loss analysis etc.
CHS boilerI put a CHS85 in my own house last year. It's a good boiler - nice control and display, versatile piping,runs quiet. No problems with it at all.
WB verses SBIf you look at the output charts for given average water temps with r 1 floor covering.
SB 105 avg. WT 17.5 btus sf
WB 105 avg.WT. 23 btus sf. .5 gpm
These are with an r 1 floor covering which is another thing you have to look at when you get your heat load done is what floor coverings you are going to use as this affects output.
Now the reason WB has more output than SB is the thickness of the aluminum. On the panel. SB is pretty thin at .002.
I'm not saying SB won't work, but its output is a little weaker. It all depends on your heat load.
radiant panelsThe finished floor will be 3/4 solid oa, no doubt the W.B is better and has thicker aluminum but the S.B is thicker than the zurn the contractor originally wanted to use and it's plywood not MDF. In my case it was a compromise due to budget.
Just pointing it outGrand view not saying SB is a bad choice just a little less performance, and more tubing to get it. 8" vs 12" centers. Completely understand budget constraints.
Keep us posted as things progress please.
Boiler choiceGrandview , You may want to check out HTP . You can do both jobs with one unit , take a look at the Versa Hydro , Phoenix or if you MUST have 2 pieces of equipment try this Versa Flame with a storage tank . Large heat exchangers , lots of mass (less short cycling) , real good efficiency . They even have a real nice video with some Dan Holohan guy looking at some of their stuff . Just my .02 !You didn't get what you didn't pay for and it will never be what you thought it would
Under CabinetsPutting heat under the cabinetry is not a big expense but can provide big dividends . Look up Mean Radiant Temperature . Most kitchen cabinets are on outside walls and will conduct cold from the outside . Guess what happens when you walk by or stand next to a big cold surface in your nice warm house ? Anyone care to guess . that is almost the same as saying it does not make sense to install under shower floors , tubs . No , Grandview I say install under all of it and increase your MRT . Not installing under them is just like the difference between WB & SB , a lost opportunity for Thermal transfer . Anyone agree ?You didn't get what you didn't pay for and it will never be what you thought it would
Depends RichIf you so happen to have a cabinet with baskets for potatoes, and onion, bread etc the stored items could do with out heating.
You could not really depend on that output under cabinets to off set the losses in the room.
The biggest MRT factor would be the countertops so apply the radiant loop to the counters, then you could off set some losses, and have a nicer MRT.
Put the tubing where it will have the most output otherwise its wasted.
One thing could be said is running tubing under cabinets may be conducive to lower pressure drop in loops with less bends in a layout vs working around cabinet layout, but that all depends on the layout of the cabinets vs the kitchen area.
tubing under cabinetryIn my case, none of the cabinets are on outside walls. The guy from North East Radiant planned the system tubing not to run under the cabinets. When I asked him about it prior to layout, he said he thought the tubing shouldn't go under the cabinets.
GordyI don't believe onions , bread and potatoes would mind a 72* ambient temperature as much as your belly would mind a large wooden surface with a large stone surface on top of it sucking the heat out of you . I have found through going on "my heat isn't working well , installed by others calls" that in the design stage these gurus did not enter unheated area w or w/o loops in the calcs . This will always lead to low SWT's or a lack of heat , probably doesn't matter much because they are the same guys whom set their mixing valves and outdoor reset curves to the wrong parameters too , 110 SWT = 115 out and 105 back , you know .
I am that nut that insists on control is all . I often will leave the tubing out from under cabinets at the floor level however and opt to add that tubing in contact with the top , same with whirlpool decks and the like . At least your not losing that square footage and believing that you can deliver the same comfort with less emitter . Just sayin .You didn't get what you didn't pay for and it will never be what you thought it would
Accounting forThe lack of radiant surface should be a given in the calcs. But the toe kick area will retain a lot of the heat in my opinion given the 4" air space thus warming the interior of the cabinet a little warmer than 72* . Applying the tubing area to a more freely radiant surface would be more effective, like you said counters, and surround surfaces.
But if your willing to lay a little extra tubing can't hurt other than what I mentioned as a concern. But I would not count in my calcs for full potential output. If your short there is always radiant ceilings or walls to make up the short fall even panel rads.This post was edited by an admin on June 1, 2013 12:26 AM.
Rob and others at NRT are usually pretty good designers . I doubt you have anything to worry about , they would have certainly made the appropriate SWT and output per sq ft adjustments . Was just pointing out because someone else may be reading this and using the information that is not involved with an educated designer .
People building their own house may not be aware of the things Gordy and others here are . Some designers / installers are in fact poorly trained other than what the supply house salesman told them or designed for them . That is why so many radiant jobs get installed so poorly . Does not seem that you suffer that possibility though .You didn't get what you didn't pay for and it will never be what you thought it would
NRT-NEH-WTF?:)thanks Rich, glad you like NRT but I'm using NEH :) Hope you like them too:) In fact has anyone out there used them:)?
NRTLMAO . Grandview , NRT is North East Radiant Tecchnologies , the guys you atated have done your design .You didn't get what you didn't pay for and it will never be what you thought it would
my loop layoutHere's my loop layout if anyone has some input. I'm assuming most will agree the loops should be under beds? Small closets I'm assuming not, except walk-in.
Looks goodFrom what I can see Grandview.
I can't really read the columns with circuit lengths, but swear I see 340' as one of them.
Water temps 110* is that correct?
This post has been deleted!