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Venting Wet Returns

cdmcdm Posts: 73Member
I have seen several posts on venting wet returns on one pipe steam systems - What advantage does this add one pipe steam system.



  • Large vents on the dry returns allow the air to escape so the steam can get in. The radiator vents are too small to handle this job, without burning excess fuel to force the air out.—NBC
  • Jamie HallJamie Hall Posts: 12,152Member
    But there's no point to venting a wet return -- if that is what it really is.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • FredFred Posts: 8,281Member
    @cdm , I think those posts you refer to are from someone who thought/thinks venting a wet return helped their situation. Don't vent a wet return. It is a waste of a good vent and likely will spew water. Serves no purpose.
  • cdmcdm Posts: 73Member
    Thanks for the response - Since the wet returns are at the end of the main last feed. I also could also not see why an additional vent was required.

  • FredFred Posts: 8,281Member
    Let's make sure we are really talking about a wet return. A wet return is a return that is below the water level in the boiler. Any returns above the water line or at the end of a main, after the last radiator run out is basically a "Dry" return and can benefit from venting. Once it drops down and is below the boiler water level, it is filled with water and there is no benefit from venting those wet returns.
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