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noisy check valves in steam condensate line

Tom_80 Member Posts: 22
Could the pump be cavatating? What is the NPSH requirement of the pumps?


  • noisy/chattering checks in condensate line-steam system

    I've recently repiped the return lines and added a dual pump condensate receiver tank to a pair of steam boilers.The original installation was using a hartford loop one punp control and one pump constantly flooding one boiler or the other or leaving me with a low water condition.I brought in a local steam specialist in the area to bounce ideas off of before beginning this job.I now have a larger condensate tank with dual pumps ,dual pump controls and seperated the condensate return lines eliminating the hartford loop.there is 3 low water cutoffs in each boiler 2 auto reset one manual reset.now every time either boiler calls for water the pump runs then the hammering begins it sounds like a single cylinder tractor idling. I originally thought it was water hammer due to the cold water on start up but hasn't went away.I have found if I cut the ball valves back to 50% it slows the duration and lessens the decibel level.If I close the ball valve right after it pumps it stops and doesnt return until it pumps again.Ireplaced the original check valves with anti slam spring checks and still does the same thing but again with less duration and less intensity. Can you give me any ideas? thanks mike
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443

    ... kirsner.org - He's got a number of articles on waterhammer on his site. There's one "Bangin' In The Boiler Room", that will likely help you.
  • joe lambert_2
    joe lambert_2 Member Posts: 61
    I have seen before

    It could be water slipping back from the boiler through the check valve when the pump is off. Try a soft seated check (of good quality)and it may help. Although there are lots of causes for water hammer and it is hard to troubleshoot without a lot of other information....
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