Advise to find a slow leak in CPVC

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nyoung, Jun 9, 2014.

  1. nyoung

    nyoung New Member

    Messages:
    5
    Location:
    Alabama
    I have installed rough CPVC supply lines on my project and need to locate a slow leak prior to connecting to the water main. I have a rig that I've built with an air hose coupling, gauge and shutoff valve. The air was added to a pressure of ~90psi. It drops about 1 psi every 3 minutes or so. I have used soapy water on all joints and caps but cannot locate it. I have used cpvc to brass unions and push-fit brass ball valves below each faucet, hose bibb, shower valve, etc. The shower valves are installed, no cartridges in them, and nipples and caps on the drop ears. My assumption was that I would find the leak at one of the sharkbite ball valves but I haven't found it yet.

    Is there some dye product I could inject into the system to help me find it?
    or any other 'tips'?


    BTW - I understand the danger of air pressure and plastic pipes.

    Thank you!
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,115
    Location:
    Bothell, Washington
    If you have 90 PSI, you would hear the leak.
  3. nyoung

    nyoung New Member

    Messages:
    5
    Location:
    Alabama
    Well that's what I assumed but certainly cant hear it (I actually cant hear real great anyway...). So even though its only dropping 1 lb every couple of minutes?
    Thanks Terry, Awesome website you have Sir.
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,115
    Location:
    Bothell, Washington
    I think you've done all you can at this point.
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,249
    Location:
    Land of Cheese
    The nice thing about CPVC is if you hook up the water and do find a leak, it should only take a few minutes to fix.
  6. Reach4

    Reach4 Active Member

    Messages:
    2,385
    Location:
    IL
    Can you borrow a child to listen?
  7. Terry

    Terry Administrator Staff Member

    Messages:
    15,115
    Location:
    Bothell, Washington
    I wouldn't want any kid of mine near plastic pipe with 90 PSI of air in it.
    I think he's fine, and should turn the water on.
  8. nyoung

    nyoung New Member

    Messages:
    5
    Location:
    Alabama
    'borrow a child' I got a laugh. Yeah, gonna skip on that one.
    I pushed it to 100 and searched still no hissing, and that's really higher than I feel comfortable going. I went ahead and closed all the valves to hoepfully isolate but it's still leaking. Just puzzled at where is the leak. Maybe the water wont find it (sound slike famous last words...).

    Thanks all!
  9. Reach4

    Reach4 Active Member

    Messages:
    2,385
    Location:
    IL
    Seriously, there is danger?

    There are ultrasonic leak detectors available for about $50 and up.
  10. SHR

    SHR Member

    Messages:
    108
    Location:
    Minnesota
    I would bet your shower valve bodies are not sealed tight without the cartridges in them. Shut off the ball valves to the shower valve and see if it makes a difference. I agree with Mr. Love that you should hook the water up and you will find out if you have a problem right away.
  11. Terry

    Terry Administrator Staff Member

    Messages:
    15,115
    Location:
    Bothell, Washington
    I've been around pipes that have been air tested. It's one of the reasons I run copper on air lines at gas stations.
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    o NOT use a dye, use water.
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    quote; It's one of the reasons I run copper on air lines at gas stations

    I suppose the second reason would be that the code REQUIRES copper or steel for air lines.
  14. Terry

    Terry Administrator Staff Member

    Messages:
    15,115
    Location:
    Bothell, Washington
    And that's the other reason.
    I remember thirty years ago, a client wanted plastic air lines. Not going to happen.
    And testing copper with air was even scary. I was on a condo project with four other plumbers. Someone forget to solder on caps, and those things were blowing off like bullets.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    quot; Someone forget to solder on caps, and those things were blowing off like bullets

    Just don't solder copper nails to them. Otherwise you will need to use a cat's paw to pull them out of the ceiling, or your leg.
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