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One cold radiator...

Hello Everyone,

I'm having a bit of an issue here. One of my second floor radiator is not getting steam at all. I changed the air vent on it, took the intake piping out to make sure it is not clogged and also checked the gate valve to make sure it goes up when I open it.

I do feel a tiny bit of air coming out of the air-vent for 2-3 seconds and that is it. I also hear "boiling sound" from the boiler when I open the valve and less noise when closed (this was done when I separated the radiator from the pipe).

What could be stopping the steam from reaching that particular radiator? Someone told me there could be an air bubble or vacuum near that piping. All other radiators nearby and the one directly beneath it are working.

Thank you in advance for any tips.



  • Cold Radiator

    You didn't mention whether this was a one pipe or a two pipe steam system. Based on the radiator having a vent, I'm assuming that this is a one pipe steam system.  Does the radiator have slope towards the steam pipe?  It maybe that the condensate isn't draining out and is blocking steam from entering the radiator. Use a carpenter's bubble level to check this as in older houses the floors can sag and what looks sloped may actually be level or sloped the wrong way. Does the radiator get warm at all?  Does  the radiator "directly beneath it" share the same lateral pipe off the main? If so, have you tried closing the lower radiator and seeing if it makes any difference on the upper radiator?

    - Rod
  • Timco
    Timco Member Posts: 3,040

    I have backflushed a radiator with a garden hose attached to the kitchen faucet and the vent tapping and it worked very well to clear an obstruction, but you have to be ready for the surge of debris in the wet return. In my case the run to that radiator was nearly completely blocked and flushing it worked well.

    Just a guy running some pipes.
  • Guest_5
    Guest_5 Member Posts: 35
    one pipe system

    Thanks all, it is a one pipe system.

    I was thinking about maybe it is some obstruction in the pipe as well.
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