Replacing Thermal Expansion Tank

Discussion in 'Water Heater Forum, Tanks' started by zaedrus, Apr 12, 2010.

  1. zaedrus

    zaedrus New Member

    Messages:
    2
    Location:
    indianapolis
    Howdy!

    I'm replacing my 2 gal. thermal expansion tank due to a pin hole leak.
    I've charged the new one per the mfr's directions.

    When I went to pull the old one off, it wouldn't budge.
    I just used a wrench on the hex end of the pipe, and another wrench on the hex of the tank.
    I'm afraid of using too much force and busting the pipe it hangs on.

    Any tricks I might try?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    If you grab the pipe properly, it will NOT break off no matter how much force you apply to the tank.
  3. zaedrus

    zaedrus New Member

    Messages:
    2
    Location:
    indianapolis
    Heheh... this begs the question - what's the right way, and what are the many wrong ways? Thanks for the input!
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    You may need two wrenches...hold the one wrench on the threaded T while using the other one on the tank. the goal is to prevent excess torque on the pipe and fitting. I've only replaced a couple, but they spun off without tools without problems. Teflon tape verses pipe dope may make that easier when the time comes, or both.
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Mmmm great advice! Tasty Fried Spam Sandwiches...

    [​IMG]
  6. gabby

    gabby New Member

    Messages:
    6
    Location:
    s.c.
    I bought a new expansion tank but it had no direction in it. It was the last one they had at HD an it had been open. Do these things need a charge per the mfr's directions?
    Also mine is full of water so it is going to be a mess when I remove it. At present it is laying over on its side full of water. I guess the bladder inside must have gone bad.
  7. gabby

    gabby New Member

    Messages:
    6
    Location:
    s.c.
    Is there no pressure on these things when you remove one of them? Sort of scary removing it.
    Mine is laying over on its side full of water.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    When you turn off the water and open a hot tap, that will relieve the pressure.
    The pressure in the tank should match the incoming water pressure.
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