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steam air vents

Big Al
Big Al Member Posts: 35
My understanding of those thermostatic valves is that they work by not allowing the air in a radiator to vent until the room temperature falls below the dialed-in setpoint. At that point the radiator heats up and throws off heat until the entire system shuts down and fills with air again.

It would make sense to me that in a house or small building, this would happen frequently enough to control the temperature in that room. In a 10 unit building, wouldn't the boiler stay fired most of the time? (Maybe not with single pipe steam.)

In that case, would smaller radiators or covering part of the radiators make sense?

I'm no expert . . . just a guy with another question.


  • ann_5
    ann_5 Member Posts: 1
    steam air vents

    We have a one pipe steam boiler for a 10 unit building. The folks on the 1st floor are too warm when the folks on the second floor are cold. We're hoping steam air vents might help. Does anyone have any suggestions as to which one may work best, and any tips to go along with it?
  • These work well

    one pipe steam thermostats

  • David Nadle
    David Nadle Member Posts: 624
    Turn it around

    The thermostatic valve also stays open until the room gets too hot, then closes, preventing more steam from entering. It *effectively* reduces the size of the radiator.

    In my (limited) experience with TRVs in too-hot rooms, you have to combine the TRV with a bit of slowness in venting to reduce overshoot.

  • Big Al
    Big Al Member Posts: 35

    That makes perfect sense.
  • Brad White
    Brad White Member Posts: 2,398
    Really two devices in play here

    Noel's suggestion to use the thermostatic radiator vent valve (TRV) is essential- high limit temperature control for every radiator or room in which it is used.

    The Macon OPSK is a personal favorite of mine but the Danfoss and Amaark also have merit. They have integral vacuum breakers, essential to their operation. One has to "take your finger off the straw" to allow condensate to drain back between cycles.

    The other part is the air vent itself which screws into the body of the TRV. As David noted, it is important that the venting rate be fast enough to bring in steam when you want it, but not so fast that it happens much sooner than the rest of the system.

    The TRV just says, "I am full, no more steam please", sort of a Yes-No valve, although they really do modulate a bit.

    When the TRV is fully open to allow air and steam in (the room being below setpoint), the air vent then says, "steam, come in, but at a certain rate. Don't outrun your siblings and don't run with scissors." I just made that last part up.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • JK_3
    JK_3 Member Posts: 240
    More about your system?

    Is this an existing system? what changes do you know of that have been done to the system? if it is an older system it most likely worked well at on time but my experience is that to many people over to many years have tried to adapt their solutions to what should have been minor repairs or alterations that you now have a bunch of little bandaids where one applied correctly would be much better .

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