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I searched high and low in the archives for an answer to my question, but if I somehow overlooked it, forgive.
I’m on the path of radiant floor heating (not to be confused with the path of least resistance), and I’m looking for some advice and a new source of income. Not to worry, I’ve come here for advice. My plumber-contractor, a friendly busy sort, finally sent me the specs on the size boiler I’d need, along with all of the other geegaws to awaken my slumbering PEX tubes in the increasingly cold concrete. I’m what you might call, a motivated buyer, but his estimate for the size of boiler I needed gave me pause. He recommended a Teledyne Laars system that has an output range of from 100,000 to 150,000. It seemed to me that our (cold) house is not that big, so I went online, downloaded an hvac calculator and figured lost btu’s myself. I came up with lost btu’s per hr. of 52,000. I double-checked everything, added the 20-25% they recommend for blizzards and such, and I was still well short of seeing a 100-150,000 btu boiler in my future. I called my plumber-contractor and asked him to suggest where I’d gone wrong. He faxed me his report, and lo and behold he had all of the wall insulation wrong, no floor insulation at all, and a surprising number of windows listed that I’ve never seen, not on this house anyway. So, I called him back, explained the discrepancies I’d found, told him it was probably my fault, anyway, something I’d said, you know, but considering everything, wouldn’t a 75,000 btu heater be sufficient? (Do men hate it when women mince around as much as women hate it when they feel compelled to do so?) Sigh. But, right after I minced, he said, not really. He said, that wasn’t enough difference to worry about, the smaller boiler wouldn’t be that much cheaper, and that oversizing had more to do with air conditioning than boilers, where bigger might actually be better. Then we talked about the domestic hot water, and he said for that reason, too, he recommended the big system. He may be right. I hope he’s right, this is his business and I know very little about it, but my gut suggests he might just be covering his ass-umptions. Worse, it’s getting cold and I need to make a decision. Does anyone have anything to add to my worst best guesses?
Replies
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Britt-
I am not the resident expert here, there are others who will no doubt weigh in, but I have reasonably considerable experience with Teledyne-Laars equipment. First, more info will help. I'm assuming that your future boiler is a JV 125 or JV 160. More importantly, what types of heat are in the house? Is it all radiant floor, or are there other types as well? How do you intend to control it, i.e. outdoor reset, floor sensor, etc.? Also, will it be used for domestic hot water? If so, is it the T-L Mini-Combo?
Also, where are you located?
I don't want to scare you, but I have recently had a few problems with Teledyne-Laars equipment. Nothing major, but aggravating. I have about 5 or 6 that I installed that I have never had problems with, but recently I had 2 others that had faulty igniters (models with hot surface ignition).
If your plumber is familiar with T-L boilers then that may not be a problem. I am not trying to suggest that you switch boilers, but just passing along a little info.
Oversizing may not be a major problem by a small factor, but your plumber has to understand how to hook up a primary-secondary system. T-L boilers are low mass, which means they have relatively small amounts of water in them and consequently need good flow and a return water temperature that is less than 30 degrees below that of the output temp. With radiant heat you typically have relatively low flow rates, and cooler than normal return water temp., so you have to have a bypass that basically pumps water in a loop throught the boiler to keep good flow and high return temp.
The more oversized, the bigger the problem.
I don't want to go on at length. If you give us some more info, it will help. I also don't want to scare you away from T-L boilers. If your plumber has faith and experience with them then trust his judgement. Personally I am looking at other boilers for future installations. But if your plumber is a professional then discuss this with him but ultimately he is responsible for picking the right materials and equipment for the job.
*Thanks very much for the information. I'll ask tomorrow for the model #. He only referred to it as the "heatmaker." T-L's website made no reference to such a thing. The house is supposed to be all radiant heat, most in floor, some baseboard (100 total feet of baseboard). However, I'm not ruling out the possibility of burning cheap furniture, bad books, tattered clothes, and old hens in the not so distant future. I'm located in southern Illinois, so I have weather comparable to St. Louis. My plumber contractor said they also carry Weil-McLain, but he quickly steered me away from that model in favor of T-L's btu range. I'm not scared, exactly by what you said about the recent T-L trouble, but, realistically, I live in the boondocks. This could be a problem. Oh, and yes on the outside temperature sensor thermostat. That popped out on the itemization as a $980 item, but from what little I know, worth it. I'd love to cut some corners somewhere on this project, but I haven't seen where to yet. Aside from the poured in concrete part (~700 sq.ft.), there will be another 800 sq. feet or so of tubing in aluminum plates on 1x6 sleepers (Wirsbo). Then, upstairs and also in the old part of house, the baseboard I mentioned before. Rambling. But thanks again.
*I knew I forgot something. Yes, it is to be used for domestic hot water as well. He said the domestic unit would fit right under the boiler, all in one, so it sounds like the mini-combo.
*Britt- If it is the Mini-Therm, then the biggest model is the 125, which has a input of 125,00 Btu/hr, but a heating capacity of 102,500 Btu/hr. This is normal. The 102,500 is the number to worry about, and since you say you have a heat loss of 52,000 Btu/hr., plus 25%, or 65,000, plus capacity for domestic hot water, then I would say that you're in the right range. The next model down only has 82,500 Btu/hr, which might be cutting it close. I have installed two Mini-Therms, and they both have performed well. There are other combo boilers, but I think the Mini-Therm is priced competitively. In any event, as long as your plumber knows what he is doing, it should work well for your house. I hesitate to second-guess your plumber, but another boiler I might consider would be a Buderus. They seem to have an excellent reputation among HVAC types, and they have some unique features that lend themselves strongly to radiant heating. They are a little pricier than Teledyne-Laars, but I am looking into them for my next boiler installation.
*I went back to the T-L website, and judging by the specs I wrote down, 95% efficient, high/low operation, 102,000-175,000 (sorry, I think I got that wrong first time.), the unit he's talking about looks more like the Endurance boiler/water heater or maybe the condensing boiler, which seems to be an on demand system and the only one that claims 95% efficiency. I looked for a local Buderus dealer on the B website, alas, nothing south of Chicago (relatively speaking.)
*It is actually a Trianco Heatmaker (recently purchased by Teledyne-Lars). Do you know anything about them?
*Britt - I don't know anything about that type of boiler. If you trust your plumber, then go with the equipment he has spec'ed. If you don't, then he shouldn't be your plumber. As I said, ultimately he is responsible for the proper functioning of your system. Good luck.
*I don't have experience whith that particular boiler but my experience with combined backaged heat and DHW systems hasn't been very good. Usually the best choice is a medium to top of the line cast iron boiler with an indirect DHW storage tank such as Ergomax, Phase III or others. Get something that doesn't use manufacture specific parts.
*I've read about your system in other postings and been curious about why you don't like combined systems since that's the direction I seem to be heading. Are manufacturer specific parts more expensive, less reliable? Unfortunately, space is an issue for us; we're fitting the system beneath a stair landing. seven feet tall by eight feet wide, three feet deep, if it will fit there. How big is a Buderus boiler anyway? These things always look big in the pictures. And, have you mentioned before what controller you use? I'm choosing between a Tekmar 371, and the Buderus Ecomatic. Since yesterday, I've been busy, both attempting proper insulation techniques (where angels fear to tread judging by the lively debates) and making phone calls. The Teledyne Laars/Trianco Heatmaker gave me cold feet. I talked to my plumber about Buderus, having been sold on it by "you guys." Unfortunatel, Buderus is a brand my p-c's never heard of, so I asked him if he'd install one if I found one -- no hard feelings -- and he said yes, so I'm pricing a Buderus from a neighboring state distributor. Buderus will work with a number of generic parts, won't it? This is all getting complicated and the days are getting shorter. I agree wholeheartedly with Nick about the trust element re: my contractor, but trust is a relative thing and my current contractor is the only viable option I've found (I live in the heart of the heart of the boondocks.) And the boiler is the only sticking point out of the rest of the RFH system. In the end, I have to pay for it and live with it, so I can't feel too terrible about questioning my p-c's judgement.
*Britt,Proprietary are more expensive, often harder to get and SOMETIMES less reliable. I have found that the thermal envelope is much more important than the heating system but they are both important. A wall hung boiler such as the Monitor with an indirect tank such as the Ergomax would be where I would start looking for your installation (cramped space). I prefer a high mass well insulated boiler most of the time but if done properly, low mass works very well too. I use honeywell controls when I can. My own system is lucky to have the same controls for more than 2 months befor I change something. The Ecomatic is a very good control but only works with Buderus boilers without modifications. The Buderus boiler is about 22 inches wide if you have access to the front, rear and one side it would work well (one side against a wall). Buderus boilers are simple, well built and well designed.Go to http://www.heatinghelp.com for info on low mass applications. There are a lot of "wet heads" there with experience with systems like what you need too.Keep packing in the cellulose and keep us updated.
*Nick,After contemplating the plumber trust issue, and calling around about a Buderus boiler, I decided that maybe you were more right than I initially thought. Maybe, I just needed to go on faith with the proposed system, or get another opinion from another p-c. Called Wirsbo, got a list of authorized dealer in downstate Il. Only other listing was two hours from here. Called them, and discussed what I was interested in, basic system specs. etc. This outfit sounds very knowledgeable, puts in two or three rfh systems a week BUT he quickly said I should go with a water heater NOT a boiler. Scrap baseboards upstairs and in old house. Save big money. He gave me their website which has a proposed system for a 2,400 sq.ft. house (roughly our size). http://www.hvacdealer.com/wintersenergy/radiant.htm It's very different than the system I've considered, but he didn't like anything about the system I described except that it was radiant. I read a recent posting about why more people didn't go with rfh systems, it seems to me exhaustion must factor in there somewhere. It is delightful that there are so many variables, but really, how's a layperson supposed to know whether to trust plumber A or plumber B when it comes to choosing x, y and z? I'm replying this not to you, personally, you've been very considerate and generous with your time and information (thank you) and more to the world at large, which just so happens to include plumber-contractors. So, I'm sending off my house plans to the plumbers who believe in water heaters. Their plan, I must say, looks considerably cheaper than my current specs, although I'm not interested in choosing a system just because it's cheaper. Anyway. Thanks again for your comments.
*Hi Britt- In all your searching, did you find anything interesting about outdoor boilers? My PEX tube salesman suggested investing in one because you save so much in "make-up air", but my plumber doesn't know anything about it. I am in the same situation as you-- PEX tubes all installed, but not hooked up to anything. I am finding that notmany plumbers around here are experienced in the whole thing, and there are just so many options it's getting confusing. I really don't want to blow it after all the money/time invested so far in tubing, concrete, etc. What did you finally decide? Any advise would be appreciated! -Becky
*I'm afraid to even read this thread.Can someone email me and tell me how it all turned out?Just a little tickle for your thoughts
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I searched high and low in the archives for an answer to my question, but if I somehow overlooked it, forgive.
I'm on the path of radiant floor heating (not to be confused with the path of least resistance), and I'm looking for some advice and a new source of income. Not to worry, I've come here for advice. My plumber-contractor, a friendly busy sort, finally sent me the specs on the size boiler I'd need, along with all of the other geegaws to awaken my slumbering PEX tubes in the increasingly cold concrete. I'm what you might call, a motivated buyer, but his estimate for the size of boiler I needed gave me pause. He recommended a Teledyne Laars system that has an output range of from 100,000 to 150,000. It seemed to me that our (cold) house is not that big, so I went online, downloaded an hvac calculator and figured lost btu's myself. I came up with lost btu's per hr. of 52,000. I double-checked everything, added the 20-25% they recommend for blizzards and such, and I was still well short of seeing a 100-150,000 btu boiler in my future. I called my plumber-contractor and asked him to suggest where I'd gone wrong. He faxed me his report, and lo and behold he had all of the wall insulation wrong, no floor insulation at all, and a surprising number of windows listed that I've never seen, not on this house anyway. So, I called him back, explained the discrepancies I'd found, told him it was probably my fault, anyway, something I'd said, you know, but considering everything, wouldn't a 75,000 btu heater be sufficient? (Do men hate it when women mince around as much as women hate it when they feel compelled to do so?) Sigh. But, right after I minced, he said, not really. He said, that wasn't enough difference to worry about, the smaller boiler wouldn't be that much cheaper, and that oversizing had more to do with air conditioning than boilers, where bigger might actually be better. Then we talked about the domestic hot water, and he said for that reason, too, he recommended the big system. He may be right. I hope he's right, this is his business and I know very little about it, but my gut suggests he might just be covering his ass-umptions. Worse, it's getting cold and I need to make a decision. Does anyone have anything to add to my worst best guesses?