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Steam Boiler replacement BTU question

<a href="file:///C:/DOCUME~1/John/LOCALS~1/Temp/msoclip1/01/clip_filelist.xml">


I am changing my steam

boiler from oil to gas. I currently have a HB Smith boiler with a Beckett

blower with a .85 nozzle. I looked at the Weil McLain instructions on there

website and calculated my radiators to be only 46,905.04 BTU’s. I also have a

hot water loop in the basement with a ten-foot baseboard. The plumbers I know

tell me I should use a 100,000 BTU boiler. Is that too much?  I just want it to be efficient as possible.

The system I use now seems to use a lot of oil for a small house, total 1066 square

feet for the first and second floor. My roofline is steep so the second floor

has a lot of un insulated roof on the walls but the attic floor is insulated.</a>


  • JohnNY
    JohnNY Member Posts: 3,230
    Boiler sizing

    There is no good reason to install a boiler that is more than twice the size needed to fill radiators with steam.

    It leads to inefficiency and imbalance.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
  • Steamhead
    Steamhead Member Posts: 16,842

    if it's using a lot of oil, the boiler may or may not be the problem. Have you had a Steam Man look at your system?

    Try the Find a Professional page of this site.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Tim McElwain
    Tim McElwain Member Posts: 4,625
    Based on your

    BTU on the radiators a boiler around 75,000 is more than enough and if you get a Mod/Con boiler with outdoor reset  you will be able to dial it in for real good efficiency and comfort. I would also however have a heat loss done on the house to be able to match that up with the radiation. I might also suggest TRv's on the radiators with constant circulation.
  • Tim McElwain
    Tim McElwain Member Posts: 4,625
    Whoops I should go to bed

    I am tired I didn't realize your boiler was a steam boiler, sorry. Still I would have a heat loss done and as Steamhead suggested you may have issues with the system itself.
This discussion has been closed.