Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Help with shutting off living room radiator

Building was built in 1932 here in San Francisco, CA. We have a steam radiator in the living room that I would like to place a saltwater reef aquarium in front of. The aquarium is full of very expensive coral and livestock that do not do well with fluctuations in temperature. I have completely shut the valve, but steam is still audibly heard entering the radiator and giving of some serious BTU's.

The thermostat has an electronic knob that controls the temperature, but even when in the off position, the radiator is heating up.

Can I have a hydronic specialist cap the pipe where the valve currently sits to completely eliminate this problem, or is there an easier fix?

I also believe that everyone in this building has shut off their valves...the heat is very uncomfortable and have already talked to a few neighbors who have shut their valves. I am guessing this is causing additional pressure?

I need to move this tank ASAP as I was planning to do so today, but when I shut the valve last night and found the radiator still hot as Hadies, I had to call off the move (4 friends, vacuum assist handles on rent at $25.00/day and countless other preparations on hold...)

Thank you very much for your much needed assistance!


  • Rod
    Rod Posts: 2,067
    Shutting Off Radiator

    Hi- If this is a one pipe steam radiator ( only one pipe attached to the radiator) there should be a radiator vent on the opposite end of the radiator from where the pipe is attached.

    The vent will look like silver bullet pointing straight up. Turn the vent so that the "bullet" i facing straight down and this should shut off the steam to the radiator. If the vent looks like a can of cat food on its side you can try turning the vetn upside down but it isn't as affective as shutting off the steam as turning the bullet type upside down. Post a picture of the radiator (showing the fittings on both ends ) as this will give us a better idea of what type of steam system you have.

  • MDNLansing
    MDNLansing Member Posts: 297

    If the radiator has an air vent on it you can turn the vent so it's upside down. Or remove it and screw a plug into the hole.
  • SF_SteamStop
    SF_SteamStop Member Posts: 2
    edited November 2013

    Yes, it does have a bullet shaped valve on the end and is a one pipe radiator. I will turn this upside down!

    Why does this work?

    Thanks, I will try this now.

  • MDNLansing
    MDNLansing Member Posts: 297
    No Air

    Turning it upside down closes the vent and prevents air from escaping. If air can't leave the radiator, steam can't enter. Even though steam and vapor is a gas, it works a lot like a liquid. Think of it in terms of water. If the "blue" water can't leave the radiator, the "red" water can't enter and displace it.
  • Steve_175
    Steve_175 Member Posts: 234

    Has anybody thought of turning the thermostat down? Are there other units that are cold? Could you post a pick of the boiler system?
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!