Testing CPVC. How long should the pressure stay at initial PSI?

Discussion in 'Plumbing Code Questions' started by OHIOresident, Feb 21, 2012.

  1. OHIOresident

    OHIOresident New Member

    Messages:
    15
    Location:
    Ohio
    I am trying to test some new CPVC plumbing I installed. If I pump the PSI up to 100lbs, it holds at that PSI for a few hours, but by the next day it is down to around 80psi. All of this plumbing is in an unheated area for now, so the temp in the building is between 20 to 35 degrees. Would the temp cause the PSI to drop over night? I have checked all of the fittings and can't seem to find any kind of leaks.
  2. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    What are you using to pressure it up with? I personally wouldn't use air.
  3. OHIOresident

    OHIOresident New Member

    Messages:
    15
    Location:
    Ohio
    Yes, air. That is the norm for around here. It is just not advisable to pressure it any higher than 100psi.
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    If the temperature is constant, the pressure should be constant also. There will be roughly 1 psi difference for every 10 degree change in temperature.

    More often than not, one of the leaks is in the test fitting.
  5. OHIOresident

    OHIOresident New Member

    Messages:
    15
    Location:
    Ohio
    Thanks for the info. I guess I need to look at my plumbing job again. The temp is only varying by 20 degrees either way, so my pressure change should be nowhere near 10-15 lbs. I will check the test fittings first. The decrease in psi is so slow I can't seem to locate it. Thanks again.
  6. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    I always install a ballvalve then install the schrader air valve into it. After I fill the system I turn the ballvalve off. This way my schrader air valve cant leak....and its common that they do.

    catcher chick is giving good advice.

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