Pressurized Expansion Tank filling up

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nin28, Apr 15, 2007.

  1. nin28

    nin28 New Member

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    I have a pressurized expansion tank installed after my hot water heater. The tank now has filled up with water and is now leaking. Question 1: Is it installed in the correct spot? Question 2: Can I just go out, buy a new one, and put it back into place? Are there any adjustments to make? Thank you.
  2. Gary Swart

    Gary Swart In the Trades

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    7,386
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    Yakima WA
    I sounds like the bladder has failed. To replace, all you need to do is turn the water off, unscrew the old tank, and screw the new one in place. The tank should be pressurized to equal the PRV setting. Watts recommends using a hand pump,like for a bicycle, but if you are careful, a regular compressor will work. Just remember the volume of air is actually quite small, so go slowly and keep checking with a gauge.
  3. Between the cold water inlet shutoff and the top of the water heater.....is preferred by plumbing inspectors in my area.

    Tank pressure when empty not installed on the system yet is to be pressurized to the working static pressure of your home to prevent premature wear....but not to exceed 80psi, as per Watts mfg. specs.

    Your tank is defective.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,268
    Location:
    New England
    While it will work where you have it, it won't last as long. The manufacturers spec them to be on the inlet side (cold water) from the waterheater.
  5. nin28

    nin28 New Member

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    45
    Unfortunately there is really no place to put the device where it should be. I'm worried I may have to replace this every year. I'm at work right now so I will check layout at home later and see if there is any other place to put it. Thank you for the help.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,268
    Location:
    New England
    You can T into the cold supply anywhere and insert this...it doesn't have to be right next to the WH; it just needs to be on the WH side of the PRV or check valve. Closer is better, but not absolutely required.
  7. nin28

    nin28 New Member

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    I'm not an experienced plumber at all and I've never installed a T on copper pipe. I was planning on cutting about a 1/2" length of the 3/4" pipe out, and then using a SharkBite T and connect it to the Expansion Tank. Any suggestions before I do this? Thank you.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,268
    Location:
    New England
    The instructions should say how much gap there is between the pipes when installed - on a 3/4" fitting, it might be more than 1/2". You could probably measure how far the pipe fits into the fitting, measure the entire distance, then figure it out, but the instructions should say. It should work if there is any slop in the pipes. If they are anchored on either side of that fitting, you won't be able to spread them enough to insert the fitting. In these cases, a repair fitting is often used. This is a fittign without a stop in the middle. You prepare the connection (clean and flux) slide the fitting over one part of a section of the pipe, place the new section (yes, you need a section) in place, then slide the coupling over the two ends then solder it in place. This can be done when both sections are anchored and cannot be spread apart to get the fitting in, since the sleeve is pushed entirely out of the way first. Hope that is clear.
  9. nin28

    nin28 New Member

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    Everyone, thanks for your help installing the Expansion Tank. Its installed and seems to be working fine. However, there is always a however, the instructions state to inflate the bladder up match the water pressure of the house, which is 80psi. I was only able to get it up to 65psi. I have a 150psi compressor and hand pump and was not able to get it any higher. Also, now I get a pulsing water supply whenever we run the hot water for a while, ie: when we take a shower. Any ideas why this would be happening?
  10. The maximum pressure on that expansion tank is 85psi on the bladder side. If you set it to 80, you are within 5 pounds of maximum and most if not everything made in plumbing will not last long with that scenario.

    80 dictates no protection on your main line. Get a PRV installed, set it down to 60 on both the PRV and Expansion tank and you'll get a normal wear life.

    If not, GOOD LUCK
  11. nin28

    nin28 New Member

    Messages:
    45
    Thanks for the quick reply Rugged. We actually do have a PRV installed and the pressure was set too high. I knocked it down to 60psi and did the same to my expansion tank. I will wait until someone takes a shower again and see if we get the knocking in the pipes. Like everything in this house we just moved into, nothing is installed or configured correctly. It has been a learning experience to say the least. Once again, thanks for the help!:D
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