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Checking Main Vents for leakage

Wondering if...besides STARING and WATCHING ...if there was a way to see if one (or more) of my main vents are leaking steam? The water in the boiler seems to be disappearing a bit. No water hammer. No sagging mains. Boiler is a Slant Fin Galaxy about 8 years old. All rads pitched to supply side. I have had no problems at all up until a week or so ago when I noticed the water was not at its usual level. It is not disappearing enough to set off the LWCO nor the auto fill, but I'm thinking one of the vents in the system may be to blame. The 8 radiators in the house currently have new Gortons installed. The kitchen rad has a Hoffman 1A. I don't see any of the individual rad vents leaking steam, but I am under the impression that they could be without noticing it!


  • Jamie HallJamie Hall Posts: 12,124Member
    It's unlikely. But it's a little hard to tell! One possible test would be to wrap paper towel or tissue around the outlet and see if it got damp...
    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
  • Another way is to hold a small piece of glass or a mirror up to the vent hole and see if it fogs up or forms condensate.
  • Mark NMark N Posts: 1,087Member
    I would tighten the packing nuts on all of the radiator valves and repack if needed. Also check that the union nuts on the valves are tight and not leaking.
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