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boiler sizing

smokeygeo Member Posts: 1
My parents have a 2,200 sq ft house and a 300,000 btu/hr gross input steam boiler (weill mcclain). It's a monster. They said their contractor "just replaced the old one with the same size" 20 years ago. But heat never gets to the upstairs of their 2-pipe system.
It's hard to do a radiator sizing b/c most of their radiators are behind fixed cases but my guesstimate is 600 sq ft of steam compared to my house where I measured all the radiators using the on-line guides (and the 175,000 btu boiler does great w/ the 475 sq' of steam I have).They have a lot of big radiators.

Any suggestions for them?


  • Jamie Hall
    Jamie Hall Member Posts: 23,430
    Problem is almost certainly not the boiler. Make sure the pressure is limited low enough -- no more than 1.5 psi. Make sure all the traps are working (even one trap failed open can mess up a whole section of a heating system). Sounds obvious, but make sure there are no odd valves somewhere which are closed.

    Where are you? They might benefit from having the system gone over by a person who is a steam expert, and if you let us know where you are we just might know someone.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 16,889
    What Jamie said. This sounds like a Vapor system. You need someone who understands these grand old systems.

    Can you see any manufacturer's names on any of the original valves, traps, or any devices in the piping near the boiler? Also, take some pictures and post them here so we can have a look.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service