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What are all the causes that will make a pressure relief valve trip on Steam Boiler?

Dairon421 Member Posts: 39
Just wanted to know so when I go on a service call I can check everything.


  • pecmsg
    pecmsg Member Posts: 2,014
    What formal training have you had?
    a short list of special tools?
  • Jamie Hall
    Jamie Hall Member Posts: 15,934
    edited February 13
    Root causes? Or just cause? The two proximate causes are first, and overpressure in the boiler. Second, a faulty valve.

    But if you are facing the first proximate cause -- an overpressure in the boiler which actually trips the pressure relief valve -- don't even think about the valve. You are going to have to find out why the pressure control device didn't trip or, if it did trip, why it didn't shut down the boiler. And that is a subject for a small book.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 9,086
    Bad pressure control, or one set to high. Plugged pigtail or plugged boiler connection
    or bad safety valve
  • bburd
    bburd Member Posts: 180
    edited February 14
    Burner primary relay contacts stuck closed. Extremely rare, but it happens.

  • mattmia2
    mattmia2 Member Posts: 3,156
    Note that if the relief valve blows on a steam boiler because it is over pressure, it usually is very violent, once that pressure is released the entire contents of the boiler is now superheated and can almost instantly all flash in to steam which can burn your skin or the inside of your lungs.
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