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Should radiator valve with vent key be replaced?

I have a single pipe steam radiator system in my house. All of the radiators have adjustable vents with the exception of the bathroom radiator. The bathroom radiator has a vent key type valve that I have come to find is either on or off and when I manually adjusted. This radiator just seems to blow lots of steam the whole time the system is on. I have been reading up a lot on steam heating systems on this site and I have come to realize that the radiator valves should close when they come up to pressure. My question is, should I replace this vent key type valve (I guess it is actually a technically a bleeder) with a "normal" adjustable valve? If I remove this from the radiator can a valve with a 1/8 inch valve usually just be fitted into one of these easily? The whole reason I want to replace this is so I have more control over the valve


  • Fred
    Fred Member Posts: 8,541
    edited February 2015
    That key vent is to bleed air out of Hot water systems. somewhere along the line, someone added or changed out that radiator. The vent should be removed and the opening plugged with a 1/8" plug. If the radiator is usable for steam, you should find a demple (in the center of a round circle) at about the center of the radiator, on the side opposite the steam pipe inlet. You can drill and tapp that location for a regular steam vent.
    BTW, your picture does not show. Message says "Page Not Found"
  • Jamie Hall
    Jamie Hall Member Posts: 21,573
    yes -- do change it for a steam radiator vent.

    Which, incidentally doesn't close on pressure, but on temperature or water. That way, it senses the presence of steam because it is hot, and closes.

    Which leads to the next point -- steam systems require very little pressure to operate; a few ounces to a pound, at most. If you feel ambitious, you might take a look at your boile and see if you can see what sort of pressure it is running at and when it shuts itself off.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England