Joined on January 9, 2009
Last Post on December 10, 2013
@ December 10, 2013 2:13 PM in radiant service in MinneapolisThey are already doing this in some desktop computers. You know those lithium cells about the size of a US Quarter in there? They power the clock so it will be pretty near the right time even if you turn the computer off for a while. Those things last about 7 years, and since many people keep their computers for less than that, they never have occasion to change them.
Now some desktops (and perhaps laptops too) have a super capacitor (5.6 Farads capacity at about 5 volts that can keep a Cmos clock chip running for a long time. Not 7 years, but if you turn the computer on every week or so (I do not know how long you can go), it recharges the capacitor. Now 5 Farads at 5 volts will not power your Tesla automobile more than a foot or so with the lights and A-C off, but it is already practical for some things to use capacitors instead of primary or storage batteries.
@ December 8, 2013 2:24 PM in Coal Still Feasible?My dad bought a coal fired forced hot air furnace (it came with a house) just after World War II. It worked. He had to put coal in it once or twice a day. He also had to take the ashes out once a day and put them in a galvanized ash can. And I had to help him carry them up the stairs and out to the street once a week to be collected. But by about 1950, the city stopped collecting ashes, so he had a gas burner put in, firing into the ash door at the bottom of the furnace. In those days coal was from about $4/ton to $7/ton. It was cheap because other users (Bethlehem Steel and Republic Steel, and all the public schools, and most of the homes burned coal as well), so the incremental cost of getting coal from Pennsylvania for houses was cheap when they were sending coal trains into the city every day anyway.
So aside from the technological issues, you may have econo-political problems, such as compliance with environmental laws, ash removal, and even getting the coal at a reasonable price.
@ December 4, 2013 1:15 PM in gas conversion in weil mclain sgo3 oilThe installation manual says all you have to do is change the orifice disk between the gas valve and the venturi. This is a brass disk with a hole in it, and is numbered for the boiler size, the fuel type, and whether it is for high altitude of not. There is a factory kit for this. I do not know what is in the kit, but surely there is the orifice disk, and probably some O-rings.
The manual does not say so, but I assume you will do a combustion test after changing this.
I worry if you do not know where to get the kit that you may not have the training and equipment needed to do the job, especially the combustion test. If you do not do this kind job as a regular thing, you may wish to get a suitable professional.
@ December 3, 2013 11:22 AM in Putting system together - pump selection helpOversizing a mod-con is usually a very bad idea. I calculated out the heat loss of my house, when it was 0F outside at about 30,000 BTU/hour. And design temperature around here is 14F. My former heating contractor suggested a 105,000 BTU/hour boiler to be "on the safe side." He said it would modulate down to 21,000 BTU/hour so it would be OK.
That is nuts. I got the smallest boiler in the product line (80,000 BTU/hr input) that goes down to 16,000 BTU/hour. And that is no where near low enough. Since most mod-cons have turn down ratio of 5:1 or so, you will never get them to go down far enough at all times. And if it does not go down far enough, it will cycle, perhaps rapidly. And you do not want that. One zone needs 6250 BTU/hour when it is 0F outside. So if it is 50F outside, it needs even less. I wish mine would turn down to 1000 BTU/hour, but it doesn't.
@ December 3, 2013 10:27 AM in Something NewYou left out one detail: Does the Taco panel still work? If it does, what a neat product endorsement!
Looks as though there should be a grommet or something there where the low voltage end switch control wire goes out to wherever it goes. And the wire needs to be replaced.
@ December 3, 2013 8:26 AM in Adding ferrous to closed systemI am a homeowner, not a heating professional.
My heating system has two zones: one is radiant in a slab at grade. The other is baseboard upstairs. Originally, there were coin vents in the upstairs zone, but when I did my system over a few years ago, I had my former heating contractor replace some 3-foot long baseboard units with 14-foot long ones, and he removed those vents. He said they were not needed.
Now I have a fancy microbubble resorber (not an air scoop), that has a vent (of course) that can be closed off, but I do not turn it off. There are reasons to turn them off, and there are reasons to leave them open, so you may be told both from one contractor to another.
If your circulator(s) do not pump away from the expansion tank, and if your system pressure is a little too low, you may pull air into your system if you leave the automatic vents open. Hence the recommendation to close them.
But if your system pumps away from the expansion tank, and your system pressure is correct (about 5psi above what you calculate to get the water to the top of the system), you should be able to leave the vent open
If the system is really old, it is possible that the seat of the vent valve would deteriorate or leak because of dirt in there. For me, this is not a problem because even if it leaked, it would just dribble a bit of water onto my garage concrete floor. But if it is upstairs somewhere in your house, or worse, in a wall (very bad), you would have serious trouble.
@ November 29, 2013 8:51 PM in Maximizing efficiency of a mod con questionI am not qualified to respond to most of your post. But any return under 130F with a gas-fired boiler would be in condensing mode, but the lower the return temperatures, the more condensing you get. If you return water at about 130F for a typical mod-con, the boiler efficiency would be about 88% (just barely condensing). If you could run with the return water at about 80F, the boiler efficiency might be as high as 97%. So design your system to get the heat you need with the lowest possible return temperatures. I hope you will have outdoor reset on this unit so it can reduce the supply temperature as it gets warmer outside and return cooler water in warmer weather. That is where a lot of the savings will occur. Design temperatures occur only about 2.5% of the time..
@ November 29, 2013 8:01 AM in Carbon Monoxide Issues - HELP!"Are there any you would suggest?"
I am a homeowner too. I read about these on this web site a couple of years ago, and I have the 2010, 2011 or so model.
Strangely enough, they come with a long-life lithium 9-volt battery that lasts only about 3 months. A regular 9 volt battery lasts about a year. My theory about that is that the lithium ones cost a lot more, so they spend a long time on the shelves and in the warehouses, so by the time you buy one, their shelf life is almost over. So unless you can be sure you are getting fresh ones (and if you can, let me know how), use the regular ones and replace them every year.
@ November 27, 2013 9:00 AM in Homeowner Heat Loss and ODR Curve LearningSeveral different ways.
1.) Default was +|- 5F from the manufacturer. I kept the default values for everything unless I had a good reason to change them.
2.) The greater the differential, the more expansion and contraction noise in the baseboard zone.
3.) I did increase it some in my baseboard zone because that zone is way too small for the modulation of the boiler. I can make it go down to 20% firing rate, but no lower. And since that zone consumes only 6250 BTU/hour when it is 0F outside, and since design temperature is 14F, it cycles too much. The lowest the boiler will go is to 16,000 BTU/hour. I did several things to help that, but now I have it run +7|-8F as part of what is needed to reduce the cycling rate to an acceptable amount. It cycles a little too much on very warm days outside, but that does not happen much.
@ November 27, 2013 8:52 AM in sandy revisitedI know. You are just not up on your vampire history.
Vampires cannot see themselves in a mirror.
@ November 27, 2013 8:49 AM in Radiant LetdownI do not have a mix valve for my radiant, but do not need one.
My boiler has two reset curves. One is used when putting heat into the radiant zone. The other is used when putting heat into the baseboard zone.
If both zones call for heat at once, the priority system supplies radiant zone reset curve and temperature to both zones. Putting radiant temperature water into the baseboard produces some heat, but not really enough.
After 1/2 hour, if baseboard zone thermostat is not satisfied, it gets priority for 20 minutes. In that case, the circulator to the radiant zone shuts off, and the boiler supplies baseboard reset curve and temperature to the baseboard zone only. Then it reverts to normal priorities and temperatures for 30 minutes. Rinse and repeat.
Since my baseboard zone takes very little heat, this is sufficient.
@ November 26, 2013 9:00 PM in air collecting in one baseboard onlyThe plumbing on my system (a mod-con with outdoor reset) is just like one of the diagrams supplied by the boiler manufacturer. My installing contractor put a Taco microbubble resorber in the system where the boiler manufacture said. The boiler is piped primary-secondary. Let me call one loop the boiler loop, and the other, the sysem loop. There is also an indirect water heater connected across the boiler loop. I would have put that microbubble resorber in the boiler loop, since the temperature in that loop sometimes goes to 175F, where the system loop, where the manufacturer said to put it, never goes over 135F. It seems to me that it is less effective there. The Taco unit works much like the Spirovent.
See pages 2 and 4 of this document to see what I am talking about:
To complicate matters, the main load in the system loop is the radiant slab that is lower than the boiler. The other load is some baseboard that is above the boiler, and has no vents at all. The installing contractor said they were not required, and that has been proved to be true. There is a purge valve for each system loop, however, to get the big bubbles out.
I do not know the flow rate through either system loop, although I have guessed it. The results depend on how good my assumptions are, and my guess is that they are not very good.
So any air in the baseboard will have to be forced down by the high water flow in that zone, or it will have to be dissolved in the water, heated in the boiler, and removed by the resorber. I think it is the latter because once I had to have the circulator replaced, and that got some air in the system. The technician purged the zone, so heating it does work, but the noise of the air is annoying until it comes out, and that takes several months because the temperature rise in the system loop is fairly small. When it is warm outside (outdoor reset), the supply temperature in the system loop is about 110F and the return temperature may be 109F or 110F. So, since it is not heated all that much, not much comes out in the resorber on each pass, and it takes a long time. After the air is out, it stays out, however.
@ November 24, 2013 8:13 AM in pump turns on and off constantly then works normal sometimes??"electric radiant heat in the floors. it worked great the first 8 years
but the last two years ive had a recurring problem with it turning on
and off over and over. sometimes it works like normal but sometimes i
hear the pump kick on for a minute or less then it turns off then a
couple minutes later its on and off again"
What pump when you have electric radiant heat in the floors?
@ November 22, 2013 11:40 AM in Radiant floor heat not heating properlyIn another field, I had occasion to describe someone who "did not have 12 years of experience: she had the same six month's experience 24 times."
@ November 16, 2013 7:42 PM in System LayoutIt gives some layout of radiant in-floor systems as examples of the points he is making. But since no two homes are alike, they are not really suggestions. He gives the principles that you would need to apply to any particular installation.
@ November 16, 2013 7:37 PM in 100 gal ao smith water heater misteryWhere I live, the gas mains in the street were nominally 15 psi, though when they metered it, it was about 8 psi. This in the summertime. This summer they replaced the old iron pipe with about 4 1/2 inch or 5 inch plastic pipe down the main street, and kept the 3 inch plastic pipe that runs from the mains down my street. It is supposed to be 50 psi, and that is what the meter said.
They said my meter and regulator could deal with the higher pressure and I would have less problems in the wintertime. Well, I did not have problems in the winter time. They checked every house pressure after the regulators, and presumably they were all about 7 inches; mine was 7 inches just as before. The meter should not be affected since it comes after the regulator.
But if your regulator was old, perhaps it could not manage the new supply pressure and is putting out to high a pressure. Gas company should be able to measure it for you.
I am looking for advice so when I spend my money it is on the best parts and layout to make the system as efficient and reliable as possible.
@ November 16, 2013 6:41 PM in System LayoutYou might consider spending your first few dollars getting and studying this book. It will give you the understanding you will need to better design your system.
@ November 15, 2013 1:29 PM in Ceiling Radiator Knocking"Ask the maintenance man. He should know."
Perhaps he should, but he may not, and rather than admit it, he may lie to you.
Like my former heating contractor. They send out a guy to do the first annual maintenance on my W-M Ultra 3 mod-con boiler. The first thing he asked was whether it was oil or gas. I sent him on his way, and soon after, did not sign up for their annual maintenance plan that was way too cheap: under $100/ year. Even for free that kind of help would not be a bargain. I switched heating contractors.
@ November 7, 2013 11:12 PM in Boiler make and modelsIt may be that you have to run a higher temp water in the rads than the in-floor heat. And that would have nothing to do with whether your boiler is condensing or not.
To get the best results from a condensing boiler, you will want to have as low a return water temperature as possible. I sometimes get return termperatures of about 75F from my in-floor heating zone, but almost 110F from my baseboard zone.
To get the best results from a non-condensing boiler, you will need a much higher return water temperature to prevent destroying the boiler. I am not an expert, but I gather you will need to have return temperatures of the order of 140F, although I have read that a few can go down a little lower. Rely on the experts here for the correct number.
If, in fact you are getting enough heat with the low temperatures you report, then if it were not for the cost of replacing a working non-condensing boiler with a condensing one (with outdoor reset), you would be justified to replace the existing boiler right away, since operating the non condensing boiler at the temperatures you report is going to destroy it in short order anyway. I suppose the vent pipe will be the first to go, then the boiler castings.
If you cannot replace the existing boiler, you will want to get some temperature mixing valves and stuff so that the minimum temperature returned to your boiler is over 140F, and that the temperatures delivered to your heating zones, especially the in-floor zone are as low as you are using now.. Fixed temperature mixing valves should be able to regulate the temperatures supplied to the radiators and the in-floor zones. Protection of the boiler is a little more complicated, but it can be done. Whether the cost of all these valves (some of them are pretty clever), is worth it or not I cannot say. At some point going to a mod-con boiler may even be cheaper, especially in the realm of comfort and fuel cost.
Since your system has enough heat emitters to heat the building at such low supply and return temperatures, it seems to be an ideal setup for a mod-con boiler. The only question I would have is if you can get a small enough mod-con boiler; i.e., one that will modulate low enough on warm days.
@ November 6, 2013 11:15 AM in Help Evaluating a Quote"I also got ahold of "Charlie from wmass" today. He's coming out on Friday to take a look."
@ November 6, 2013 9:45 AM in Homeowner Heat Loss and ODR Curve LearningSure I noticed a difference in my utility bill, but that means very little. Very little because I took out a 60 year-old oil burning boiler when heating oil was almost $4/gallon and installed a brand new W-M Ultra-3 modulating condensing boiler burning natural gas at about $1.30/Therm and for all I know the number of degree-days was different from one year to another. Also, I replaced an electric hot water heater (with a very slow leak) with an indirect running off the new boiler.
"How did you know you had good results"
That depends on what you and I mean by good results. For one thing, since I have a radiant slab at grade heating the downstairs, I want to run that slab at a constant temperature. Otherwise the temperature overshoots by about 5F after the thermostat us satisfied, and undershoots several degrees when the thermostat calls for heat. That is what it did with the old boiler with no outdoor reset. With the outdoor reset, I tried to supply the water to the slab at just high enough temperature to make up for the heat loss, and it took a while to determine those temperatures and adjust the reset curve accordingly. A side benefit of doing this is that the supply temperature is often about 76F (until it goes below 50F outside) so I get lots of condensing.
One way to judge is to notice when the thermostat is calling for heat and if it is set up "right" it will call for heat for a long time. For my slab, it sometimes calls for heat for 18 straight hours.
For my baseboard zone, I cannot do it as tight because the boiler is too oversized and will not modulate down far enough. To get around the rapid cycling, I put a minimum of 110F into the baseboards and let it get up to 136F on really cold days (it never got that cold around here since I got the boiler about 5 years ago). Otherwise I might let it get down to 90F or something on warm days. But the idea is to get the supply temperatures there as low as possible, consistent with getting enough heat. Upstairs, it may run 4 hours or so sometimes, but I have never gotten as much as 12 hours. If that zone had more heat load, perhaps I could get it to run longer, but I do not choose to leave the windows open there in winter just to make the boiler run more efficiently. I guess if I felt like burning that much gas, I would put snow melting under my short driveway and my 180 feet of sidewalk. But I am too cheap for that.
"Differential of 30*F (no change)"
Mine is 15F, and the default from the manufacturer is 10F. The greater the differential, the greater the expansion and contraction noise from the baseboards and associated piping. I would lower my differential to 10F, but then the boiler cycles too much when heating only that zone. My boiler will modulate down to only 16,000 BTU/hour and that zone can take only about 6.250 BTU/hour on the coldest days, so I had to do something.
@ November 5, 2013 5:24 PM in Homeowner Heat Loss and ODR Curve LearningMy Cape Cod house is in Monmouth County, New Jersey where the design temperature is 14F. I did a heat loss calculation of my house three different ways.
1.) I looked at the existing oil-fired boiler that was going to be replaced and it had a 1/2 gallon per hour nozzle in it, so that comes to about 70,000 BTU/hour. Since that boiler always provided enough heat, that was the upper limit of what size I needed. The installing heating company recommended a 105,000 BTU/hour unit "to be on the safe side." This is the worst way to size a system, I think.
2.) The manufacturer of the mod-con gas fired boiler has some worksheets to calculate heat loss, but they are not very accurate. I got something like 40,000 BTU/hour if I remember correctly.
3.) I used the Slant/Fin program that used to be available and got something like 32,000 BTU/hour. This was probably the most accurate calculation.
Calculations 2 and 3 are all somewhat too high because they assume design temperature of 0F and around here it is 14F. I did not bother fixing that because the smallest boiler I could get in the product line was 80,000 BTU/hour input (about 72,000 BTU/hour output).
I figured out what temperatures at the high end and low end I would need from the size of the baseboard units in the upstairs. When this system was installed, I increased the baseboard in each of the two rooms from 3 feet to 14 feet units so I could run lower water temperatures and get more condensing.
For downstairs, where the slab at grade contains copper tubing (1/2 inch) I had to guess the length and spacing of the tubing.
In any case, when I used the results of the calculations, it did not work all that well. I did not make any calculation errors, but estimating the transmission of my walls was problematical because I could not see inside them. They are pretty well insulated, and I had just installed Marvin gas-filled double windows, so they should be pretty good. But there are some air leaks, and I do not know how much.
I imagine with the heat loss calculations more accurate than mine (mine failed because that data I put in was not accurate enough) you could compute the water temperatures at each end of the temperature range you need to match the supply water temperatures to the heat loss of the building using simple high school algebra. But it sure did not work for me. (By the way, my boiler supports a separate reset curve for each of the two heating zones, and a fixed (adjustable) temperature to drive the indirect hot water heater.)
In any case, the water temperatures were by and large too high for optimum condensing, and the thermostat in the baseboard area shut down pretty quickly. So I lowered the temperatures at both ends of the upstairs reset curve, The big problem is that I could not (of course) adjust the outdoor temperatures. So on a pretty warm day, I set the end of the reset curve down until it worked OK, but as it got colder outside, that was off, so I adjusted that, etc. It took about two years of tweaking to get it to match the heat loss of the house so that the supply water temperatures were as low as I could get and the thermostat would call for heat for many hours at a time. Ideally, if I could get it right, I would not need a thermostat at all, but that assumes the wind outside blew at constant speed because outdoor reset cannot cope with variable air infiltration.
Downstairs in the radiant zone was even worse because it takes about 24 hours after adjusting a temperature until the system recovers from the change. And by then the outdoor temperature has changed again, adding to the confusion.
When all is said and done, I have, in the same format as yours, given first:
WWSD at 68*F
Design Supply water temp at minimum design outside temp: 201*F
Differential of 30*F
Min Outside Design Temp of 5*F
Max Outside Design Temp of 68*F
Design supply water temp at Maximum outside temp 95*F
WWSD at 70F (manufacturer's default: I never changed it.) Both zones.
Design supply water temp at minimum outside temp 136F
Differential +7F, -8F (total 15F)
Minimum outside temp of 6F
Max outside temp of 50F (if it gets hotter outside, it holds the setting until WWSD is reached)
Design supply water temp at maximum outside temp of 110F. The reason I have it this high is to reduce short-cycling. Also why I have such large differential.
Radiant Slab zone
Design water temp at minimum outside temp 120F
Differential +5F, -5F (total 10F)
Minimum outside temp of 6F
Max outside temp of 50F (if it gets hotter outside, it holds the setting until WWSD is reached)
Design supply water temp at maximum outside temp of 76F.
If you lived next door to me, I would suggest starting with these settings (same builder, same basic house design) and tweak them from there. It would take you perhaps two days if the outside temperature would be very warm on one of the days, and extremely cold on the other day. Unfortunately, those two days might not even be in the same month, but over a year or two you can get close enough.