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Steam radiator hammering & spitting a lot of water

I suppose that, generally, this is a fairly common problem, but not for me, and I'm having trouble finding threads that suggests possible fixes. I have a very vertical greystone house, circa 1900, with steam heat. One radiator at the rear of the second floor seems to be possessed, a lot of hammering and a consistent water drip/spit. I thought it was a very occasional drip, and so I placed some folded up towels under the Durst A880B vent valve (almost all radiators in my house have this valve, the only one that's easily accessible to me at Home Depot), but then I checked it the other night and the towels and floor were soaked. I've swapped out the valve and that didn't help. Also, if it matters, this radiator hasnlt been a problem before. Thoughts? Thanks--and Happy New Year!! 


  • BobC
    BobC Member Posts: 5,480
    Something changed

    Has the pressure in the boiler changed? has there been any work done on the house that might have moved a pipe?

    Spouting of water and water hammer is a sign that water is sitting in pipes where it should not be. Steam pipes need a slight pitch in any horizontal piping so condensing steam can find it's way back to the boiler.Put a level on any horizontal pipe that feeds this radiator and make sure there is some slope.

    The Durst vent is not a good vent, you would be better served by using a Gorton, Hoffman, or Maid O mist vent on your radiators. What kind of vent does the steam main in the basement have and what kind is it? What pressure is the boiler operating at?

    Post some pictures of the boiler and the pipes around it, also post a picture of the problem radiator showing both ends. While your at it, put a level on the radiator and make sure it is pitched toward the steam input.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
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