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Steam Radiator Plug Ringing Noise

jmhold Member Posts: 10
Hello! I purchased a home built in the 1930's in November of last year with a single pipe steam heating system. After some "getting to know you" snafus, the system is working relatively well with a few caveats.

1. Most of the radiators in the house have a plug at the top/left or right side with a small "V" shaped hole that rings like an old rotary phone when the radiator is filling with steam. This noise is very distracting. (Though it may sound a little nuts, I assure you the noise isn't coming from the air vent. The ringing in the bedroom was so loud I covered the offending plug with some foil tape, which diminished the volume of the ringing significantly, so I could get a full night of sleep.)

2. I cannot find the main vent. With all the research I've done, I have never heard of a single pipe system that does not have a main line vent. Is it possible that my system doesn't have one? If so, should I have one installed?


  • Pictures of the plug??
    Some early air vents were miniaturized, and this plug may be a malfunctioning example of that.
    you could take it out and replace it with a real plug.
    What is your pressure?—NBC
  • jmhold
    jmhold Member Posts: 10
    edited February 2021

    Pressure: I tool a pic of the boiler.

  • KC_Jones
    KC_Jones Member Posts: 5,737
    edited February 2021
    That’s the original vent.  I don’t think I’ve seen a picture of one in that good of shape.  It might be making noise, but that’s kind of amazing.

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Remember that the settings on the pressuretrol may not match the actual pressures, if the pigtail is plugged.—NBC
  • mattmia2
    mattmia2 Member Posts: 9,632
    you could maybe try cleaning it

    here is a description of that vent:
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    To answer your other question, every one-pipe system should have main vent(s), but many don't. Mine didn't have one when I bought my house but it had a place where one used to be and I was able to easily restore it as one of the first improvements I made to my system.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • jmhold
    jmhold Member Posts: 10

    Remember that the settings on the pressuretrol may not match the actual pressures, if the pigtail is plugged.—NBC

    Well...I sat in front of my boiler for a whole cycle and the pressure gage never moved. It's probably stuck or broken :neutral:...
    mattmia2 said:

    you could maybe try cleaning it

    Thanks for the link and suggestion. I'll have to see if I can find an article on how to clean them. My initial thought is to try and squirt white vinegar up there. Thoughts?