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Blast Off !

alan_8 Member Posts: 19
Question: Why , basically in the morning from the start up, some radiators are hissing pretty bad, which then gets water in the radiator valves, which then basically hinders the heat in them later in the day (air not passing through valves with the water inside). I have a one pipe steam system. Thanks for your help. Matt


  • Brad White_203
    Brad White_203 Member Posts: 506
    Some mornings I wake up to

    hissing sounds and moisture too.

    Makes me wish I had a steam system :)

    Seriously, a handful of issues are likely conspiring.

    1) Lack of proper venting. If "proper" it should be silent or nearly so. Think "constricted asthmatic breathing" versus deep lung breaths.

    2) "Wet Steam"- this is caused by any number of things. Starting with the near-boiler piping, is there sufficient initial height above the boiler- at least 24", maybe more?

    Do these risers stab into the bottom of a main tee or enter the side? Or best of all, enter the top of a dropped header?

    Are these risers large enough, larger than the tappings from which they emanate? And are all potential exit tappings used?

    Are the pipes insulated (to help keep steam as steam)?

    Many things, those are but a few.
  • alan_8
    alan_8 Member Posts: 19

  • alan_8
    alan_8 Member Posts: 19
    Blast Off ! Photos


    Thanks. I have placed a photo of boiler- does it look ok? I know i do not have any main vents (just one vent on pipe looks like draining back) leading to the radiators . The header was recently replaced with with Copper when i had the new boiler installed( i orginally had black iron and are having them come back to change). What should be insulated?
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