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steam radiators will not get hot

raptor Member Posts: 1
Only one of the main floor radiators will heat up in our home. It is a 1930's steam heat system. The system is making "banging" sounds.


  • BobC
    BobC Member Posts: 5,470
    Radiators not heating

    We need a little more information. Is the water level in the boiler ok? it should be around the middle of your gauge glass. There should be a pressure gauge on the boiler and it should just read about 2 PSI when the boiler is steaming, sometimes the gauge doesn't seem to move at all because they don't work all that well down at the low end of the scale.

    Did the system work ok last year? Do the radiators elsewhere in the house work ok?

    Can you tell if the banging is coming from a specific radiator or pipe?

    Is your system single pipe steam? Single pipe steam just has one pipe going to each radiator.

    All the steam supply valves should be fully open, you cannot control the amount of heat by turning a valve partially off with single pipe steam.

    Water hammer is usually caused by trapped water and that can be from clogged air vents or improperly sloped radiators and pipes.

    Are there air vents on the side of the radiator? Usually these are bullet shaped and about half way up the side away from the input pipe. The vents should be open till steam hits them. Can you hear or feel air escaping these vents while the boiler heats up?

    In the basement there should be air vents near the ends of the main pipes to let the air out as the system heats out and to help the condensate return to the boiler as things cool down. These are open until the steam hits them, you should be able to hear air escaping or feel it escaping. Some times a piece of tissue paper can be used to see if the air is escaping.

    Steam cannot flow into a pipe or radiator or pipe unless the air can escape and all the water has to be able to flow back to the boiler.

    All of the above is valid for single pipe steam only. If it is two pipe steam, there are different rules. Two pipe steam has two pipes connecting to each radiator.

    We may also need pictures of your boiler, the near boiler piping (above and around the boiler). A picture of one of the nonheating radiators (both ends) would also be good.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • jpf321
    jpf321 Member Posts: 1,568
    see my rad-no heat troubleshooting questions...

    on this thread here (2nd post): http://www.heatinghelp.com/forum-thread/129206/Radiator-not-getting-any-heat
    1-pipe Homeowner - Queens, NYC

    NEW: SlantFin Intrepid TR-30 + Tankless + Riello 40-F5 @ 0.85gph | OLD: Fitzgibbons 402 boiler + Beckett "SR" Oil Gun @ 1.75gph

    installed: 0-20oz/si gauge | vaporstat | hour-meter | gortons on all rads | 1pc G#2 + 1pc G#1 on each of 2 mains

    Connected EDR load: 371 sf venting load: 2.95cfm vent capacity: 4.62cfm
    my NEW system pics | my OLD system pics
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