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Continuing water hammer issues

I have a one pipe, oil fired steam system with two main loops ( 'front loop' with 5 rads and 'back loop' with 3 rads) in my 1926 home. 3 or 4 years ago the old steam boiler cracked inside, sending the steam up the chimney. Not knowing much about steam boilers at the time and trying to delay having to replace the boiler, I allowed my well intentioned dad to add some sort of radiator crack sealer to the system. Not sure if that caused or contributed to the following issues. The sealer not surprisingly didn't work so I had the boiler replaced with a Burnham. Since then, I have had loud water hammer and water squirting out of one radiator on the 'back loop' (this rad had been a bit noisy even before the old boiler died). This rad starts off sounding normal, slight hissing of air leaving when heating up, them we start to hear gurgling water and water hammer and the rad fills up with water until it squirts out the steam valve. Not sure if the sealant collected somewhere in the back loop piping, this rad or if something else is going on. I believe the system was skimmed and all piping was done correctly on the install, Hartford loop etc., can put up pics. I have checked the pitch of the problematic rad, pitch of the pipes in the basement, changed the steam vents on all rads, insulated all pipes, swapped out main vents from Ventrites to Gorton 2s, flushed rusty water from the boiler- pretty much everything I have read about here or in Dan Holohan's book. Is it possible that this pipe or rad might be partially blocked, keeping water from draining? Can you scope or roto-root the pipe? Would love to get system fixed and balanced so we don't wake up to loud banging every morning at 5. I mostly try to use our wood stove now to heat due to the noise and higher oil costs. Any suggestions or qualified steam contractors in the Worcester, Ma area? Thanks for help and suggestions!


  • Double D
    Double D Member Posts: 442
    Pictures would be a good start.

    Make sure you stand back far enough to get the boiler and near boiler piping in the pictures from different angles.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    edited February 2014
    Loud recovery from setback

    Those periods of recovery put the system under a lot of stress as it burn$ extra fuel to regain the temperature in the morning. I would for the moment leave it at a constant 65 degrees or so, and see if the water-hammer is moderated.

    You will still need to find the source of the imbalance. A 0-3 psi gauge would confirm the actions of the pressuretrol. You won't be able to get down to the few ounces needed for real comfort and economy, but it will be better set as low as it will go. A vaporstat would be needed for that sort of control.

    That gauge will also tell you if you have too little main venting, or too much rad venting, by measuring the back-pressure during the venting phases.--NBC
  • Jamie Hall
    Jamie Hall Member Posts: 23,458
    Pictures would be...

    a very good start.

    However, if the radiator starts to gurgle and bang part way through a cycle, but more towards the beginning, that tells you right away that what is happening is that steam is condensing in the main -- no surprise there, and that's OK -- but that the condensate can't drain properly back to the boiler.  So it gets pushed along banging and clanging, and gets into the radiator and squoosh out the vent.

    Figure out why the condensate can't get back to the boiler properly.  Something, somewhere isn't pitched right.

    As to contractors in the Worcester MA area, you could probably persuade Charles Garrity to come that far without much trouble.  He's one of the best.  He's under "Find a Contractor" listed in Lee, MA
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England