Boderus, WM, Dual Boilers...Help

Weezbo

melt system or a large indoor olympic wave maker or outdoor heated swimming pool you arent likely to need two boilers....one 215 buderas would maybe give you a few btus to cover any excess loads in the future. a small modulating boiler for the shoulder seasons i could understand...well are you in northern Canadas central interior? i suspect their temps are much like mine short sleeve weather when it warms up to 40 below F :)

bob_48

Boderus, WM, 2 boilers....Frustration....

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 Burnam boilers 1 for radiant and 1 for the hydroair

2) Buderus looks 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. I am not sure about Burnam efficiency...but they are easy to service.

At this point I am frustrated.

Any comments or pointers are welcome.

bob

lchmb

complexity

All three are good boiler's. As to getting part's for the Buderus, I have never had an issue getting anything for them. If you do have an issue, simply contact them and they will do what it take's to help you. Have you had a complete heatloss done? Who did the design for the system and have you looked in to this company? I, for one, would look at all the option's and want a complete understanding before I gave the go ahead. I also would want to go with the best, not worry about the cost. If done right it will save you for year's to come. If done wrong, , you'll keep paying for year's to come...

Al Letellier

boiler choice

We do many jobs like yours and here are my thoughts, for what they're worth......We seldom use two boiler for a heating load this small. Have yet to see the economic sense of buying two, unless cost is of no concern. The boiler is really only the pot we heat the water in and the system and how it is controlled is what heats the house. I'm not a Burnham fan and use a lot of Weil's. We do install Buderus and they are a great piece of equipment. If your contractor is very knowledgeable about controls, you can do the job equally well with either boiler. If he lacks that expertise, Buderus is the way to go. They manufacture a control system mated to their boilers. You simply tell them what you want to do and the control comes all set up. Just mount it on the boiler and wire it up. They have excellent support mechanism in place, supurb personnel and all the parts are readily available out of your local supplier or the distribution center in New Hampshire. Never had a problem with them, ever. Weil is a great boiler too, but you have to site build the control system and it can confuse someone without the knowledge and experience in doing that kind of work. Go with one boiler. Use some of the extra money a second one would cost and invest in a good control system.
200K sounds like a lot for 5000 sq feet. Make sure a good heat load calculation is down. See it in WRITING!!!!

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Ken_8

Neither boiler

trips my trigger.

Based on the suggestion that you need 200,000 BTU's, this house better be a full blown mansion - because that's what it takes to heat a castle, not a "typical" home. My 2,000 S.F. 50 year old cape takes 34,000, and winter temps go to zero. If any contractors have suggested 200MBTU's as correct, drop them like a bad date. They have no clue.

If the house will be all cheap glass - and lots of it, or will be located in Siberia, my concern might be unfounded.

Granted, the S.F.age of a house has little to do with the heat load but generally speaking, today's well constructed homes will require roughly 25 BTU's per square foot of living, heating space. Based on the 200MBTU load suggested (granted, we don't know if that was input or net I=B=R) the house in question would be about 8,000 square feet in size.

Roughly 5 times the size of my seven room cape.

Whattaya think?

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Michal

200mbh is correct

for a house of that size, We use about 25 btu/sf times 5000 sf thats about 125,000 btuh, so 200k is ballpark when considering coil load, heat loss, glass and high ceilings inderect hot water load and radiant. Buderus is great cause you can run a greater delta t in your coil and not worry about shocking the boiler, I would use 1 boiler or 2 smaller ones on a lead lag panel for redundency wired with both to come on when load demands. Buderuses are great, I have instaled them, they are not complex, hardest thing i think is putting on the damn jacket, burner (riello) is a snap to work on. Parts are becoming very easy to get, i have not had a problem, weils are nice too, but like before buderus, you can run a greater delta t. if not sure, ask engineer for his load calcs

Rely_2

Boiler selection

is the important thing here. If your looking for good eff than choose a boiler that is condensing and have the contractor over size the coils in the air system.You can get data on the coils for btu output at 140 degree water temp.This will get the best Eff for your buck.We where using W/M Ultra but have moved to Trinity boiler for this type of setup.I agree with all who say the heatloss is way to high for this sqft house get another one and check the work.

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Boilerpro_3

Do not base load on \"X\" btu's per square foot

This is not a heat load calculation! I conducted a full blown heat load calculation on my own 1906 2 story frame home with 2,800 sq ft of living space, an unheated full basement and 700 sq ft of glass with storm windows and the load is only 50,000 btu/hr @ -5F outdoors. That works out to about 17.5 btu/sq ft. I ran for several winters with a 75% efficiency boiler at 90,000 input and the boiler never ran at full capacity.

I have a poorly insulated 10,000 sq ft church that I heated to -5F with only 190,000 btu/hr here in northern IL.
I typically go to two on/off boilers at 200,000 btu/hr, but since you probably don't have this kind of load, a single boiler would serve you well.
Burnham makes a nice simple 82% efficient power vent model, or Slantfin has a 85% efficient power vent with outdoor air intake that is no moe complex that any other power vent model on the market. Buderus has a similiar model. I myself skip the 87% models as they are as or more complex than the 90% condensing models out there, so repair costs could be less with a condensing model. A modulating condensing boiler with outdoor reset with ductwork designed for high volume, low velocity constant reset air supply temp
(supply vents high, returns low) is probably the best comfort and highest efficiency combination I have ever seen, for forced air.

Boilerpro

soot_seeker_2

Sizing a boiler

I am considering buying a new gas boiler.
My home is about 2000 sqft. I have two zone heating.
I would like to know what size boiler I should get.
I was advised that the Weil boiler CGA-6 should be sufficient. I am not sure. Please help.
The CGA-6 has the following:
Boiler
Input MBH=175
Heating Capacity=146
Net IBR=127

Constantin

Well, I am a mere fellow homeowner...

... but I echo the sentiments of others here and suggest you do a little more research.

First of all, if your home is not built yet, I would suggest looking into buildingscience.com for some very good tips on how to build an energy-efficient home on a budget. The insulation you add to the envelope now is pennies compared to the savings over the years that you will accumulate. Further, look into resource-efficient building practices, like 6" thick walls with 2x6" studs on 24" centers and dense-pack cellulose insulation.

With the right insulation package, your heat load will plummet. For example, even my old victorian home is projected to lose no more than 18BTU/(ft² x hr) in -15°F weather, i.e. 90kBTU/hr for a 5,000 ft² large home. In new construction and with the right architectual details, you should be able to do even better than that.

Furthermore, since you're interested in heating with gas, I would look into using a condensing gas boiler instead of the boilers you have mentioned. Such boilers will save you a lot of gas over the life of the unit and are an ideal match for the radiant loads. Better yet, most condensing gas boilers also modulate and therefore can match their output to your heat loss, making for a very efficient heating system. Such boilers include the Buderus GB142, HTP Munchkin, NTI Trinity, Triangle-Tube Prestige, Viessmann Vitodens, Weil-McLain Ultra, etc. (in alphabetical order).

So, I'd sit down with a good contractor and go over your options. Explore which wall thicknesses/insulation packages offer what kinds of paybacks, along with the equipment choices you can make. In an ideal world, you'd use the hydro-air units as supplemental heat sources while the radiant does most (or perhaps all) the regular heating. Also, be sure to make the space under your roof deck part of the conditioned space, so that the air handlers there can work in relatively benign conditions.

Lastly, the biggest impact on the longevity and reliability of your system is the quality of the installer and maintainers, not the actual equipment. Time and time again, the same hard lessons are re-learned when contractors take shortcuts and bad things happen. So, as a start, find a contractor that takes the time to do a heat loss and which will discuss your options with you. The Find a Professional Link at the top of each page of this site is probably a good first step.

Steve Ebels_3

A little SOUND ADVICE to all Homeowners!!

You're getting prices on a new boiler or system and your contractor says, "You need a xxx,xxxbtu boiler" or he says, "We size the boiler for xxbtu's per sq ft".

The first thing you say in reply is "PROVE IT!"

If he doesn't produce a Manual J based heatloss calculation of some type, I'd drop him like a hot potato. If he doesn't do a heat loss calc, he doesn't know. It's as simple as that. Some may be able to guess fairly close but it's still a guess. One for which you will pay dearly for the life of your system in terms of poor function, reduced efficiency, mechanical problems etc.

I could write a book about the projects we have done that are now heating with equipment HALF the size of what was proposed or installed in the first place.

Here's one: An older construction church, 7,600 sq ft., that had five furnaces in it totaling 670,000 btu's. It's now being heated, and nicely so I might add, by a single oil fired Buderus 215 firing at 294,000 input!!! Their fuel costs ar less than half what they were with the old system.

DEMAND a heatloss calculation. Don't be intimidated, it's your money and your house.

Constantin

Hear hear!

I couldn't agree more. A heat loss calculation is but the first step in the right direction, as nothing is cast in stone until the walls are finished.

Ron Schroeder_3

And if the heat loss is even close to 200K with a valid heat loss calc., fire the designer, not the heating contractor.

Ron

dconnors

Gas boiler and direct venting....

your choices with us are the GA series or the GB series. Either one will do the job and can be direct vented. Make sure of your load before buying. As far as parts and service; you can check our website for distributors in your area. WWW.buderus.net.