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Low pressure steam conversion

HNM1 Member Posts: 1
edited August 2019 in Strictly Steam
We have been contacted to bid on a residential oil to gas vapor steam to low pressure steam conversion. The supplier of the boiler, tec. support sez to just rip out the Brunell tank and pipe like any other steam change out. We know this is just wrong and are looking for some guidance on how to make this seamless. The system is over 70 years old.


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    I wouldn't call tech support with a situation like this, nor would I expect them to actually know the correct answer.
  • Jamie Hall
    Jamie Hall Member Posts: 23,289
    Your best bet is going to be to pipe the new boiler to, at an absolute minimum, the manufacturer's spec. Me, I'd go for a drop header at least one size larger than the riser(s). Hook that into the existing Brunell system, which I'd leave alone.

    You'll also need a vapourstat in addition to the pressuretrol which probably comes with it, and an accurate low pressure gauge to verify your settings (start with 12 ounce cutout, but you'll probably want to go less).

    Can you post some pictures of the existing near boiler piping? We can probably be more intelligent if we can see what's what.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 16,835
    I think @HNM1 means a "Broomell" system. HNM1, you need to get a copy of "The Lost Art of Steam Heating", which is available in the site's online store. Broomell is covered in chapter 15.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • clammy
    clammy Member Posts: 3,111
    Read the lost art ,over size your header install a vaporstat ,flush out all returns chk all cross over traps and replicate the old boiler water line not to lose water seal out in the system if u have to do it w a false water line ,and pay attention to what u change which shouldn’t be much .if possible make sure the gravitated hand valves are still in place .if you can use a 2 stage gas valve do it and replace the ain vents w Hoffmann vapor vacuum vents if you still want vacuum . Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating