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Need to know size of EGH Weil-Mclean boiler to install in a Manh

ALH_4 Member Posts: 1,790
As Steamhead already said, a heat loss calculation is <i>extremely</i> important, particularly with the type of heat loss your home is likely to have.

There is nothing saying your neighbors have properly sized boilers. You could possibly get by with anything from 200,000 to 500,000, or higher.

I assume you have cast iron radiators. Installing thermostatic radiator valves and modulating condensing boilers would be ideal. The boiler may or may not condense on the coldest day of the year, but it will certainly condense when the heat load is below design. See if the contractors you have talked with are familiar with the Weil-Mclain Ultra.

I would also recommend installing two boilers instead of one. This will let the system operate more effectively in the spring and fall when the heat load is less. There is no sense in firing 500,000 btu/h if the current heat load is 50,000 btu/h. Also, if you might consider installing an indirect water heater at the same time if you do not already have one.

With your heat load, a little efficiency adds up to a lot of dollars.


  • Correct Gas Furnace Size

    Please help us ! We have lived in this home for 50 years. In December the original coal furnace from the 1880's and converted god knows when had an anuerysm. We need a new furnace. We got several bids but noone agrees on correct size furnace. Everyone is suggesting Weil-Maclean EGH furnaces. We have hot water not steam pipes in the original 3" size. Our house is approximately 10,000 square feet, with a lot of old windows and some skylights. For the first 2 rooms (deep) there are neighboring buildings on the east and west walls. There are 2 zones and circulators. We need to decide very soon. Our neighbors have a 400,000 and 500,000 BTU system respectively. Our house is inbetween in size. THANK YOU
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Do a heat-loss calculation!

    with your system, that is the only way to size the boiler.

    At the top of this page, click on "Free Heat Loss Calcs". This will take you to Slant/Fin's site where you can download the calc program (if you have broadband) or order it on CD-ROM (recommended if you have dial-up). It will run on any version of Windows, from 98 to XP and maybe Vista too.

    Input the design indoor and outdoor temperatures. These are generally 70 inside and whatever the coldest outdoor temp is in your area. Then do the necessary measuring, type the info into the program, and you'll get your heat loss. The boiler with a NET rating equal to or slightly (NOT radically) above this value is the size boiler you need.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • tim smith
    tim smith Member Posts: 2,752
    boiler sizing

    Based on the size of house I would guess that those picks are pretty close but have all of them do a heat loss to determine the size. My guess is that the age of house dictates you have a pretty high heat loss unless it has been full remodeled in the last 20 years and all walls,ceilings and floors were insulated at that time and new windows done. If remodeled then the heat loss could be substantially lower. Heat loss and proper history of remodels will tell this. Good luck.
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