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ancient steam system knocking

mabstl
mabstl Member Posts: 2
edited October 26 in Strictly Steam

house buildt in 1929 likely original steam boiler radiator system works like a charm. Just had a corroded pipe against an outside wall replaced (abut 8 feet of return pipe) and now we have air knocking. Radiators do not have any valves on them to bleed. There is a dial at the top of each radiator for volume control. Any ideas on how to eliminate the knocks? radiator farthest from the boiler is not heating properly either. THANK YOU!!

Comments

  • Danny Scully
    Danny Scully Member Posts: 1,437

    ZERO complaints until 8 ft of wet return piping were replaced? All radiators heated perfectly with no noise until this work was done? Can we see pictures of the work done, the boiler, any exposed piping, etc. Also, where are you located?

    mabstl
  • Jamie Hall
    Jamie Hall Member Posts: 24,734

    There are no bleeders because this is two pipe steam, and doesn't need bleeders.

    Yes, pictures please and an exact description of what was done. Something got messed up… be interesting to see what.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mabstl
  • mabstl
    mabstl Member Posts: 2

    photos added

  • Danny Scully
    Danny Scully Member Posts: 1,437

    Not enough. Back up and take us on a tour of the basement. Or tell us where you’re located so we can get the right person to you.

    mabstl
  • clammy
    clammy Member Posts: 3,156

    if a 2 pipe steam and the pipe was a wet return that was replaced I would gather that there is a clog in some portion of the piping . I say this being I have seen this occur when section of a steam system wet return is replaced and not properly flushed to makes sure that in replacing the piping that more crude and debrie where loosed while the repair was being done . The banging usually occurs due to water backing up in the return piping or in your case the end of the steam main drip unless your dry return drip into a common wet return . . Usually when I’m faced w replacing ancient wet return piping adding an isolation valve and a drain for flushing only makes common sense and is common practice in my book but that’s me ,especially on older systems not equipped w isolation valves for really flushing the mud out .
    Most likely due to the age of your system there’s 1/2 a lifetime of mud and rust located within the wet return ,usually the result of decades of lack of proper maintenance or anyone w a clue as to what real steam boiler maintenance consists of . Personally you should call those who did the repair and if there clueless then ya just had a guy who replaces pipes and not really works or has a great knowledge of the finer points of steam system issues and trouble shooting . Those in the know know what to do but there never cheap being they have a good clue as to what goes on and how to resolve issues . Is there a working pressure gauge on the boiler high pressure will also cause banging especially if the pressuretrolls pigtail is clogged and your running higher then 1.5 psi most likely in your case a vapor stat should be used . Aside from a 0-15 gauge that is required by code a 0-3 psi gauge should be installed so the actually pressure in the boiler is known not assumed .
    peace and good luck clammy

    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating

    mabstl
  • ethicalpaul
    ethicalpaul Member Posts: 6,568

    The new pipe could have introduced oil into the system causing carryover which might cause knocking, but it's hard to tell from the photos what might be going on.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el