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Sizing a replacement Steam Boiler

Motlava Member Posts: 1
I have an old steel steam boiler from the 1960's with copper tube convectors. We need to replace it but I'm pining over the final size boiler. Matching the nozzle size is easy but my gut tells me its to big. Any thoughts on how to feel more confident on the size of the replacement boiler?


  • BobC
    BobC Member Posts: 5,470
    The boiler has to be matched to the load those convectors represent. You have to determine what the EDR (sq footage of surface area) of each convector is and add all of them up to determine the system EDR

    Once that is done you find a boiler that comes close to matching that number with it's Sq ft rating. The boiler Sq Ft rating already has a 33% safety factor so don't worry about any losses because of the piping.

    Is this a single pipe or a two pipe system? Post a picture of a convector with the cover off to see if someone can help you with the EDR. Also post pictures of the current boiler showing the piping around it.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge