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Steam radiator still heats with Ventrite 1 set to closed position. Leak somewhere?

To tame a huge radiator in a small bedroom that was heating too much, too quickly, I installed a brand new Ventrite 1 and for starters dialed it down to its shutoff position. I figured I'd let the radiator completely cool off and the next day experiment with opening the adjustable dial a tiny bit at a time. But with the Ventrite adjustment wheel set the entire way to the off position, the radiator still gets hot all the way across. I'm baffled. A friend mentioned that the radiator could have an air leak elsewhere allowing the air to vent out of the radiator even with the Ventrite closed. However, I hear no hissing. Any explanation for this? (background -- one pipe steam, massive main venting with Big Mouths, insulated mains, whole system as tip-top as possible considering that it is 50% oversized. Vaporstat set to cut out at 10 ounces. Pigtail clean as a whistle. Pressure confirmed by separate 0 - 3 psi gauge).


  • Steamhead
    Steamhead Member Posts: 16,262
    If you installed the vent while the radiator was still hot, there was still some steam in there. When the steam condenses, it creates a vacuum and pulls in more steam.

    Open the vent and let the system cool down completely. Then close it and see how it works.

    The only other possibility is there might be an "In-Airid" vent installed in the radiator that you don't know about. These masquerade as a plug in the top tapping of the radiator on the opposite end from the steam connection. Post a pic of that location of the radiator and we'll see.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • jhrost
    jhrost Member Posts: 57
    I had a similar situation - only the vent I was using was a varivalve. I thought that maybe the packing around the vent was bad, or that maybe one of the radiator sections had a subtle leak. I tried putting a 1/8" plug in the vent tapping as an experiment. The radiator went stone cold during the next heating cycle - even the pipe below the valve was stone cold . I tried two different vents - generously wound up with teflon tape to insure air would't get through - the radiator still heated up all the way. I can only conclude that with all these adjustable vents the "off" or "closed" is just the lowest setting, but not actually completely closed.
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    I dont think it seals perfectly. I’ve also found the wheel is not precisely postioned. You might need to keep turning it until you feel it seat, or until you can feel the air stop coming out the vent.
  • Dan_NJ
    Dan_NJ Member Posts: 223
    jhrost said:

    ... I can only conclude that with all these adjustable vents the "off" or "closed" is just the lowest setting, but not actually completely closed.

    The Ventrite #1 does close completely and as mikeg2015 says the dial numbers are not 100% dead on. You need to dial it down past 1 until it seats closed. Try the 1/8" plug in place of the vent to be sure there's no venting going on there.

    Varivalves don't shut off and I found they vent quite a bit more than I expected at lowest setting. Check the chart here:
  • WillNH
    WillNH Member Posts: 10
    For what it's worth, when I replaced all my radiator vents with Ventrite #1s, I found that some seemed to close completely when dialed all the way down (past 1), but others seemed to still be slightly open. This is based on blowing into them, so I'm not sure how accurate it is. My wife is pregnant and demands that the bedroom be quite cold at night, so I put one of the ones that did close completely on that radiator, and it's been staying nice and cold.
  • gfrbrookline
    gfrbrookline Member Posts: 727
    You can use a small screw driver to pry the wheel down a little. That will let it close completely.
  • SlapSlap
    SlapSlap Member Posts: 2
    Maybe un-noticed leak between radiator sections allowing steam to displace air and heat up radiator. Happened to me!
  • SlapSlap
    SlapSlap Member Posts: 2
    Try spraying soap solution between the sections while there is pressure in the system.
  • Dan_NJ
    Dan_NJ Member Posts: 223
    I've had good results with a mirror. You might need to be looking when the system is cranking good. I've done a 2-3 degree setback at times when leak hunting to get a good long run.