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Vents blowing air! Change header size?

Clark Member Posts: 8
Replaced 80-year-old coal-to-oil-converted boiler with a Utica PEG150 gas boiler. EDR calculations seem to be correct. Now every air vent in the house isn't just venting, they are blowing air with an irregular, quite audible hissing until the steam finally hits. Tried changing vents to larger/smaller orifice, even changed out both main vents from Gorton #1s to #2s, all to no avail. Reducing the burner output helps somewhat, but house takes a lot longer to heat. Near-boiler piping is to MFR's specs- all 2-inch 1ncluding header, then two 2-inch mains picking up 5 to 6 rads each. Would upsizing the header to 2 1/2 inch or greater help slow this sucker down?


  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Try cleaning the water side first

    there's probably a load of oil and sludge in there, interfering with steam flow off the water surface.

    If you installed tees at the steam outlets as specified, you can flush this boiler out with a hose AFTER LETTING IT COOL DOWN FIRST! Then refill, fire and skim it, and see how it does.

    But if I were installing that boiler, I'd use a 2-1/2" header.

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  • clammy
    clammy Member Posts: 2,739
    what,s the pressure

    did you adjust the pressuretroll down from the factory set which is about 5 lbs crank down your pressuretroll to 1 on the cut out abd .50 on the cut in clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • phil_29
    phil_29 Member Posts: 1

    steamhead and clammy, thanks! I will blow it down and skim. Pressuretrol is set at .5 cut in with 1.0 diff.
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