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How long does it take for water to return from radiator once heating is turned off?

Aditya Member Posts: 1
I have steam heat. I switched on the boiler. Then I let the radiators heat. Then I switched the heat off. Waiting now for all the water to recede. How long should I wait?


  • neilc
    neilc Member Posts: 1,805
    well you shouldn't have to wait,
    the water may fall an inch or so in the sight glass, but it should always still be there in the sight glass.
    Sounds like you have issues there.
    What boiler pressure are you set for?
    and what pressure do you see?
    Post pictures of the Pressuretrol, and of the sight glass,
    and of the boiler showing the pipes above to the ceiling.
    Are the radiators one pipe or two?
    known to beat dead horses
  • Fred
    Fred Member Posts: 8,518
    You're waiting for the water to "recede" from where?
  • GW
    GW Member Posts: 4,542
    You have wet or dry returns?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • mikeg2015
    mikeg2015 Member Posts: 1,187
    There really isn’t much condensate generated. 1 gallon is 8300btu. That’s about 3:00 of running for a 150k boiler. So 0.3gpm. A small stream from a faucet.
  • Jamie Hall
    Jamie Hall Member Posts: 18,947
    If you really mean recede -- presumably from some radiator or other -- there really never should be any water to speak of there in the first place. There may be some in the bottom of the radiator -- depends on how it is built -- but that will stay put. As @mikeg2015 noted, steam heat doesn't generate much water.

    If instead you mean watching the water level in the site glass of the boiler, it could easily be a minute or two after the boiler shuts off for it to recover to its original level after the pressure drops to zero. Shouldn't be a whole lot more than that, though.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England