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FST-200 Boiler Breeching Rumble after conversion to gas

jblum Member Posts: 7
There is a pronounced rumble in the horizontal breeching of the 200 horsepower FST-200 boiler with IC burner after conversion from #2 oil to natural gas.    The boiler and burner are is 20 years old and never rumbled before conversion to gas.    Part of the conversion involved installing a stainless steel liner in the vertical masonry chimney.      In the boiler room, the breeching was not changed, but it was re-insulated with lighter insulation after removing the old heavy lagging.

I am looking for referral to an specialist who can help.

Jim Blum


  • Weezbo
    Weezbo Member Posts: 6,232
    edited April 2014
    it is early , my first cup of coffee,

    is it possible the combustion air requirements have not been met?

    for a quick idea where to look?

    if the room has an opening like a window or door to the outside

    and you open it, during start up and testing ,

    your results are different than with the window or door closed ,

    Then , there is insufficient combustion air intake , for an example.

  • Weezbo
    Weezbo Member Posts: 6,232
    edited April 2014
    as i have not heard back from you

    would you consider calling the mechanical contractor who installed the burner ?

    Let them Know that this happened?

    Thank You.
  • Steamhead
    Steamhead Member Posts: 16,723
    If memory serves

    the Federal FST boilers run with a slight positive pressure in the firing zone. Check to see that the breech damper is properly set.

    What were your combustion test readings?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service