I am about to try to make a decision on a boiler(s) for new construction home.
5000sq feet, with a combo of radiant in some areas and hydroair (I beleive that is what it is called…it is integrated into the AC air exchangers and provides hot air heat). It has been sized for 200K+ BTU’s. It would be gas and must be direct vented (I dont have a chimney).
I have been told a mix of things….1) use 2 boilers 1 for radiant and 1 for th hydroair
2) Buderus is great (but I am scared of service and parts complexities)
3) Weil-Mclean “Gold” line is great use that!
4) Condensing vs non-condensing (I dont yet know the difference).
I dont know if I really need 2 boilers first of all. Second, I dont like Burnam as they are too inefficient and old school…but they are easy to service.
At this point I am frustrated.
Any comments or pointers are welcome.
bob
Replies
You may get some worthwile input here, but you will do far better by going to heatinghelp.com and posting your Q on "the Wall" forum.
That is where the plumbing and heating pros are. There are a few here, but a whole lot more there.
The best is viessmann, but its also more money. My last house we used a WM gold, its the best basic boiler. Boderus has a good rep but the viessmann is the step up. WM is a Cadillac, Boderus a Benz and the Viessmann is the Bentley in quality and in price. In time, the Viessmann will pay for itself in heat savings.
http://www.tjsradiantheat.com/heatsavings.html
Here is a line of wall hung boilers from Baxi. I replaced an ancient cast iron unit in my home with the 310Fi and we're happy with it:
http://www.wallhungboilers.com/products.html
It's a 120K BTU, direct vent, non-condensing boiler with full electronic modulating gas controls, built-in self-test diagnostics, and fully adjustable temperatues with an option for outdoor reset. The unit contains a backflow valve, expansion tank, and Grundfos 2-speed pump, so all you do is hook it up to gas, water, and the hydronic loop(s).
You probably would need two of the standard units (unless you also want DHW) for your large house, one set for the air coils, and the other set to a lower temp for the radiant tubing.
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Hi Bob,
If two boilers are going in - have them connected this way (subst. the chiller shown above with the second boiler)
This system has been piped and valved using a philosophy we teach our students which is: "Design for Failure". With the two boilers, radiant, air system - piped and valved this way its possible to have a failure in any one system yet still have heat.
As far as brands...think service. Its ok to call up the manufacturers and the distribution - ask them pointed questions like:
Who handles service and parts in our area?
How long have they been in business?
Are they factory certified?
Is there more than one certified technician on staff?
How long has the proposed models been used in my area?
Do you have names of unsatisifed customers I can call as well as those who love your stuff?
anyways you get the idea...
Remember it sucks to own anything zippy (even if it is the best) when you need parts and service at the worst time of year.
RBean
http://www.healthyheating.com
http://www.healthyheating.com/blog
Edited 2/26/2005 8:59 pm ET by RB
Edited 2/26/2005 9:00 pm ET by RB
The Munchkin boiler made by Heat Transfer Products is increasingly popular in my area. It is very compact, quiet, and appears to be well made.
http://www.htproducts.com/
any chance of using a domestic water heater for the radiant floor requirement?
I think I am ok with a single boiler. Everthing I am being told from heatinghelp.com says a single boiler is fine.
Condensing vs non-condensing refers what happens to the the flue gases in the (any fossil fuel burning appliance) on the way out of the unit and the building. Products of combustion include CO, CO2, water vapor, NOx. When all these components remain gases, they are realtively non-corrosive. For this to happen, they need to stay above the saturation temperature of the water vapor in the flue until they have left the system. If, due to improper installation, a situatiuon exists that causes condesation is a system or appliance that is not designed for this, damage could and usually does occur. With cast iron boilers for instance, you also run the risk of shocking the boiler sections and cracking the cast iron and/or causing the sections warp and/or separate. In boiler systems, this is prevented by proper design of the piping system, controls and adequate start-up procedures.
Condensing boilers/furnaces/water heaters, etc., are designed for the corrosive components that form when the water vapor condenses. Acids form and this is why high efficiency appliances are vented with PVC, and also why they have stainless steel components that are resistant to the corrosion. In the case of boiler used in low temperature applications, such as infloor heating systems, condensing equipment is well suited to the application. In the process of wringing as many btu's as possible out of the fuel, designers intend for the flue gases to cool to the point of condensation. Without exception, high efficiency (92% AFUE or higher) fuel burners are the condensing type.
It is a relatively simple excercise to have multiple water temperatures supplied from a single boiler, so as you have learned from others, no need for two boilers.
IF, I were starting from scatch, as you are, I know what I would do. I know the market and availablility of parts in my area so the brand, in my case would be Weil-McLain. Your decision would have to be based on information in your market. Utilizing a single condensing boiler as the source of heat and hot water. Variable speed air handlers with hot water and DX (i.e. air conditioning) coils and tubes in some or most, if not all of the floors would be an excelent way to go. Add an indirect water heater setup on a priority zone, and recirc the hot water and you could do no better.
Thanks this is just about how I am going but probably with Bouderus....I will verify the service and supplies in my area, which I believe are good. I will go with a 100 gal hot water storage tank. It will be condensing just based on the fact that it will be direct vented, not through a chimney. I already have the AC/Hydroair Heat installed up and Radiant in some floors (anywhere where there is ceramic / stone floors)...I opted to not do it under the wood floors. I have already requested a written Heat Loss calculation from the installer, which is not a problem. I am also sure that 200K BTU is way too much.
The Bouderus has a computer that appears to be "optional". I am curious about how you use the boiler if you do not use the computer control.
I have learned alot from heatinghelp.com and this forum.
Thanks.
"It will be condensing just based on the fact that it will be direct vented, not through a chimney."
This is not the same thing as a condensing boiler. Buderus offers good stuff, but I do not believe they are offering any condensing boilers in the USA.
Actually, Buderus does (by now) offer a condensing boiler on the US market, namely the GB142 series, which is a aluminum-HX condensing boiler. They are still working on some approvals, like Mass. code, if I recall correctly. Anyway, two things come to mind with this question:
Where is this house located that 200kBTU are needed to heat 5k sq. ft? That's 40BTU/sq ft, the kind of load I might expect in Alaska.. Our recently-reonvated house in Boston has a design-day heat loss of 18BTU/sq ft, when it's -15°F outside. Is this a snowmelt application?
I'd take a close look at the prices for fuel and base my decision from there. Natural gas is a cheaper fuel in much of the US than oil, for example. By fuel type, here are some boiler opinions:
In a radiant floor heat application, a low mass, condensing, modulating boiler like the GB142, Munchkin, Vitodens, Ultra, etc. are pretty much unbeatable in terms of efficiency when LP or natural gas are the fuel source. Even with modulation, be careful sizing the unit, the benefits of modulation only really come to those that size the top output to the top expected heat loss.
On the oil side, Buderus and Viessmann would be my top choices, with a nod to the Vitola for it's inherently shock-proof design. However, Burnham, Weil-McLain, etc. also make quality products that don't cost as much as the Viesmann. If you want to go condensing on the oil-side, you could try out the Monitor FCX. I'd wait until the US fuel gets cleaner, however.
What should be driving your boiler decision first and foremost is who will install and maintain the unit in the future. If a brand has no presence in your area, you may be setting yourself up for some long nights when things do break. Plus, installation quality is everything... someone that has a lot of experience installing the boiler of your choice. Contractors with a "boiler is a boiler" attitude should be excluded from your project.
HTH.
Someone mentioned Heat Transfer Products.
You can run a single HTP boiler and get 199kbtu (input). Better still, since it modulates, it can act like a smaller boiler when the weather is not so cold. The boiler output temperature can be setup to dynamically adjust to ambient conditions.
Lower output temperatures increase efficiency (and comfort) due to greater condensing. It can also serve up your
Closed combustion to meet your venting needs. It's a relatively good deal.
Viessmann offers up these features too, but for a lot more money.