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Condemning expansion tanks

Ken C.
Ken C. Member Posts: 267
How do you tell if a bladder-type thermal expansion tank is bad? I know about tapping on the top and bottom half of the tank and listening for any difference in sound, but I don't have enough experience to trust this method.


  • Robert O'Connor_4
    Robert O'Connor_4 Member Posts: 88

    the system down to o psi and take air presure reading at valve on the tank. If you get water out of the air valve then you know for sure the bladder is gone in the tank.


  • jim lockard
    jim lockard Member Posts: 1,059

    When the threads break off the tank because its waterlogged and sprays water all over the boiler room. Then there is no doubt the tank is defective. Best Wishes J.Lockard
  • bob young
    bob young Member Posts: 2,177
    new innovations

    maybe the leak will stabilize the pressure and you won't need a tank.
  • Boiler Guy
    Boiler Guy Member Posts: 585
    Knock on tin

    You have got to be one talented person to troubleshoot a tank by beating on it! I agree with the other post - isolate it so you can check the pressure inside at static pressure outside. If it spits at you when you touch the air valve -- IT'S DONE!
  • hr
    hr Member Posts: 6,106
    The weight of the thing

    A gentle, very gentle, shake will often tell if it is waterlogged.

    hot rod

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  • bill clinton_3
    bill clinton_3 Member Posts: 111
    bladder tanks

    Taking the pressure down to 0 and checking for air pressure in the tank will tell you the tank is bad if it spits at you. Low pressure reading will not, however tell you the tank is bad. My experience is that these tanks become waterlogged because air slowly permeates through the membrane, causing a loss of pressure and giving system water a chance to intrude further into the tank.

    We have recently taken to installing a valve to isolate bleadder tanks from the system, then installing a hose bibb between the isolation valve and the tank: Check for spitting; isolate the tank; open hose bibb to drain off pressure; with hose bibb open, grab your bicycle pump and recharge the tank to cold fill pressure.

    The only bad thing about this is you'll sell many fewer tanks :( Oh, well.
  • joe_14
    joe_14 Member Posts: 138

    right on hot rod!!!!!

  • Mark Wolff
    Mark Wolff Member Posts: 256

    I like you more every post I read. It's nice to see some smart people in business. You're right on as usual.
This discussion has been closed.