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EDR connected load question

Jim_163 Member Posts: 3
This is two pipe steam system. I calculated my heat loss using the slantfin download. I have 201,500 BTU/HR heat loss. (4200 Sq. ft. house) I include the basement,attic and garage (which is heated)I then measured all my radiators using the info/diagrams on this site. My total was 196,850 (square feet times 240 for steam) My bolier is 450K BTU. Set backs only work in increments of 2 degrees, as all the radiators get hot all the way across, and the system shuts down on pressure. I need to wait about 30-45 minutes, before I move up another 2 degrees. Here is my question,looks to me that my boiler is way way oversized, or I don't have enough radiators/connected load to facilitate the system. I'm highly confident that my heat loss/connected load calculations are good, and at the most a 10% in error. Any advice or comments would be appreciated.


  • Brad White_202
    Brad White_202 Member Posts: 105

    Assuming that your calculations and measurements are correct, the radiators and heat loss are a good match. This in my experience is rare but it also means that your envelope has not likely been improved since the house was built -or someone stole some radiator sections. :P

    Now, as you know, heat loss means bupkus when it comes to sizing a steam boiler. The connected radiation rules.

    The coincidence that yours align is a fortunate happenstance.

    I am not sure what you mean by setbacks in 2-degree increments.

    It does seem that your boiler is indeed over-sized and short of replacing it, the only option is to down-fire it. This is art as much as science. Too low and you simmer, not boil, for no purpose whatsoever as far as heat is concerned.

    How old is the boiler and is it a candidate or potential candidate for replacement?

    For that matter, is it a potential candidate for president? Domestically produced and over 35 years old?

    I will vote for it :)
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