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Water Hammer

JMO Member Posts: 2
Hi All. Let me first say this site is an awsome source of information. I have a 2 pipe venturi vacume steam system circa 1914 made by Pierce Butler and Pierce. I have a nasty water hammer with a second floor radiator. I checked the raditator pitch, which seems ok, as it slightly slopes to the supply side. I am thinking that the suppy valve has failed or is obstructed? I messed with the valves when I first bought the house and they prob had not been moved in 20 years. oops. The hammer starts near the beginning of the cycle with several (maybe 5) loud clangs followed by several(maybe 10) small and much lighter and rapid knocks.There are two other radiators down the line that seem to not produce much heat. I am thinking I can handle this myself, but would also appreciate knowing if there is anyone in the Syracuse NY area who is familar with these systems as the winter snow season is coming soon. Thanks and Happy Thanksgiving! 


  • Jamie Hall
    Jamie Hall Member Posts: 19,966
    While I am not familiar

    with the Pierce system (quite likely Steamhead is, or Gerry!) I presume that it is more or less conventional, in that the supply valve is at the top of one end of the radiator and the return at the bottom.  In which case the radiator should slope towards the return, so that all the condensate can drain.  Doesn't have to slope much.

    The water hammer you describe sounds very like what is sometimes heard when there is a horizontal section of the runout to the radiator which has sagged -- or which never was quite right.  Any horizontal section of the runout from the steam main to the radiator must pitch back to the steam main, or early condensate may collect (will collect!) and hammer until the steam fully reaches the radiator -- at which point it should stop.  Check the line from the steam main to the radiator, and make sure that the pitch is OK.

    You say there are two other radiators "down the line" which don't seem to heat much.  Can you clarify?  Are they down the line in the sense that they are farther along the steam main, or are they somehow hooked up to the radiator which hammers?

    As to the valves -- you probably didn't do them much harm.  Steam valves are pretty tough critters.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JMO
    JMO Member Posts: 2
    Thanks Jamie!

    Down the line in this case would be farther down the steam main.
  • gerry gill
    gerry gill Member Posts: 3,045
    can you tell where the steam is (by touch)

    when the hammering starts?
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Steamhead
    Steamhead Member Posts: 15,657
    Pierce, Butler & Pierce

    may or may not have made the "system" you have, though they probably did make the radiators and/or the original boiler. This company was located in Syracuse.

    Have you been able to locate any names or trademarks on the "venturi" or any of the other system hardware? Take some pics if you can and post them here, they should help us ID your system.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • gerry gill
    gerry gill Member Posts: 3,045
    do you have Hoffman return traps

    on your Pierce system? if so i could probably explain your system.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • wayne_kirsner
    wayne_kirsner Member Posts: 1
    Sure Like a Video w/ Sound of the Banging

    Of course you,ve got water hung up in your radiator so when the steam enters your're getting a condensation induced waterhammer.  You need to get the water out at shut down.

    When the system starts to heat up, you may be able to feel (or measure with an infrared run) the temperature difference between the pipe or radiator portion filled with steam vs that which is water logged (where steam can't penetrate) to find out where water is hanging up. 

    Could it be that the vaccuum created by the venturi allows condensate to drain under operation, but when the system cycles off, the vacuum is lost and condensate is backing up or somehow trapped by a rise in the line?. 

    Not an expert on these systems, just an enginner who'd like to post your video if you make one on my web site [url=http://www.kirsner.org]www.kirsner.org.
  • thanks for a cool website mr. kirsner!!

    thanks to mr kirsner's efforts, more will now be known about this phenomenon.

     hammering should never be accepted as a natural annoyance, to be tolerated as an unfortunate  side-effect of steam heating; but rather as the destructful, and wasteful result of poor maintainance!!--nbc

This discussion has been closed.