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Two pipe steam radiator banging

Hey folks, I'm hoping I can find some insights into our noisy steam heating pipes here! We moved from overseas into a 100+ year old house with steam radiators, which we have no experience of. I've had a few people take a look and tinker but nothing has helped so far.

The radiators all seem to be pitched OK and - after getting a couple replaced - all the vents are working.

The banging seems to come almost entirely from what I think are the return pipes - photo attached. It could be just one of the pipes but I can't tell which. I've noticed a slow leak from one of them recently. We had one contractor add the vents at the top of these pipes last year, and another contractor add a bit of pipe so the vents were further from the return pipes. I'll attach photos of everything referenced above


Any suggestions would be greatly appreciated, We'd love to get it fixed and silence the banging!


    JUGHNE Member Posts: 11,077
    What pressure shows on the gauge?
    What is the pressure setting on the control.....grey box with numbered scale showing on the front?

    Pictures of those items and also pictures of your typical radiator showing both ends of it.......all would help a lot.
  • Fred
    Fred Member Posts: 8,542
    Likely a trap failed open on one of the radiator returns letting steam into the return pipe. Did anyone check the traps? Near boiler piping isn't good but that's another story.
  • Jamie Hall
    Jamie Hall Member Posts: 23,453
    It's a little hard to see... I hope these are both true dry returns (and no, I'm not going there again, folks). And I rather agree with @Fred above. A potential problem that I see is that that connector between the two drips is probably at, or just above, the water line in the boiler, which is not really the best elevation.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Chris_L
    Chris_L Member Posts: 336
    Can you post a picture of one of your radiators? I am not convinced this is a two-pipe system.

    I agree with @Jamie Hall that your returns look like they are connected too high above the floor, which can cause hammer.
  • Steamhead
    Steamhead Member Posts: 16,904
    That boiler was made by Dunkirk, and the piping around the boiler is nowhere near what it needs to be for good operation.

    @scottcooper where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • clammy
    clammy Member Posts: 3,113
    From the looks of all the cooper I’m surprised you don’t have more banging w that being said your gas bill must be hi and your system performance is not what it should be and will never be great w that near boiler piping . It should be tossed and properly piped in steel pipe using both risers out of the boiler .dont let the guys who installed it do anything since they can’t read I wouldn’t let them touch anything but this is your choice ,look for a pro listed here pay what they say and get it right the first time and have a system which will perform as it should heat evenly and be economical to operate . I was recently told that just filling in your name on a sat gives you like 500 points I think those installers didn’t even get the 500 easy points lol peace and good luckc clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • gennady
    gennady Member Posts: 839
    edited March 2020
    I don't think you have 2 pipe steam system.
    In photos there are dry return pipes. Master vents installed incorrectly. They must be installed at least 18 to 24" before drop elbow.
    Near boiler piping is out of line completely. Boiler must be repiped. There is no dry steam produced by the boiler and a boiler water gets into steam mains.
    You have steam piping in the basement flooded, water there boils and creates steam hammer.
    Check steam pressure, boiler firing rate and rated input against installed radiators EDR and heat loss.
    Copper is not a good material on the steam, because sweat joints do not hold against cyclical loads.
  • dopey27177
    dopey27177 Member Posts: 887
    The near boiler piping is a disaster. Much of your problems emanate from the near boiler piping. Additionally the Master vents were not installed properly.

    See the attachments and you will see what is needed. Should you undertake replacing the near boiler piping the outlet taps from the boiler (steam supply) must not be reduced in size. The steam header for the boiler must be increased one size larger than the steam tappings of the boiler. Additionally see the proper location for vent valves.