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  1. #1
    Join Date
    Mar 2012
    Location
    Sammamish, WA
    Posts
    48

    natural gas line pressure test

    Hi all,

    For a final check (inspection is coming soon), my gas pipe was pumped up to 15 PSI. Over two weeks the gauge has dropped to around 6.5 PSI. When I checked the first night it was still right at 15, and I think (?) a day or two later as well. Then I didn't check it so often. 2 days ago it was at 7.5 PSI. With such a slow leak I'm sure that it will still pass inspection (around here it just has to hold pressure for 15 minutes), but should I be concerned at all? Or is it probably not even the lines but the cheap gauge causing the slow trickle?

    Thanks!

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    [QUOTE=Cascadian;13983001]Hi all,

    For a final check (inspection is coming soon), my gas pipe was pumped up to 15 PSI. Over two weeks the gauge has dropped to around 6.5 PSI. When I checked the first night it was still right at 15, and I think (?) a day or two later as well. Then I didn't check it so often. 2 days ago it was at 7.5 PSI. With such a slow leak I'm sure that it will still pass inspection (around here it just has to hold pressure for 15 minutes), but should I be concerned at all? Or is it probably not even the lines but the cheap gauge causing the slow trickle?

    Thanks![/QUOTE

    Soap each joint and fitting

  3. #3
    Join Date
    Feb 2012
    Location
    Toronto Canada
    Posts
    1,090
    It's leaking fix it ! Pump it back up and do a soap test.

    Or leave it and make sure you tell the inspector about your leak

  4. #4
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    My plumber has told me of one case where he couldn't find the leak with soap. The leak was a tiny void in the cast fitting. An elbow I think. I think he started taking pipe apart and capping a section and working back until it would hold pressure. This was the only tiem it ever happened to him. But he's only been a master plumber for maybe 15 years.

  5. #5
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,665
    Let it fail inspection and let contractor make repairs, if it passes you may get stuck with a leaking gas line. It will all be documented for future this way

  6. #6
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by motoguy128 View Post
    My plumber has told me of one case where he couldn't find the leak with soap. The leak was a tiny void in the cast fitting. An elbow I think. I think he started taking pipe apart and capping a section and working back until it would hold pressure. This was the only tiem it ever happened to him. But he's only been a master plumber for maybe 15 years.
    Thus the reason for checking each joint and fitting. If the right leak solution is used and low pressure the bubbles will form a honeycomb effect and increase in size, then rinse once leak has been found.

  7. #7
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    Could be the temperature. Pretty hard to get leaks in gas pipe but it happens.

  8. #8
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    When is a leak a leak or not a leak? Our gas code calls for new work in a residential application (.5 psi) test to be 3 psig for 10 minutes with no loss. In fact, gas cocks has a legal leak rate so expecting a system to test for 7-days with zero pressure loss is expecting more than can normally be delivered. Any leak that fails 3 psig within 10-minutes is definitely a leak to be located and repaired. BTB, existing work is tested at 1.5-psig!!
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  9. #9
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,760
    leak should be found and repaired.
    i just went back to a gas line i installed 3 weeks ago to remove pressure test and hook line up to furnace.
    had 15 psi when i put it on and 15 psi 3 weeks later.

  10. #10
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,665
    Quote Originally Posted by t527ed View Post
    leak should be found and repaired.
    i just went back to a gas line i installed 3 weeks ago to remove pressure test and hook line up to furnace.
    had 15 psi when i put it on and 15 psi 3 weeks later.

    My parents just bought a forclosed house built in 03'. Only had gas logs and never a bottle hooked up. Still has 15 psig on the gauge 6 yrs later. Just so happens I was the contractor on the house for hvac and gas. I am asking for a raise in the morning

  11. #11
    Join Date
    Nov 2011
    Posts
    9
    A leak is a leak.

    Inspectors in our area require 30 psi holding for 24 hours. Lose 1 psi and you flunk!

    Typical cause is either insufficiently tightened threaded joints or teflon tape not working to seal cheap Chinese threads. On the professional plumbing forums you will see lots of reports of problems with these new threads.

    Best solution we've found is forget about teflon and use the Rectorseal white putty. Never had a leak with it. Have seen cases with these cheap Chinese threads where it took 8 wraps of teflon to plug leaking threads which were super tightened.
    Last edited by etbrown4; 08-16-2012 at 10:07 AM.

  12. #12
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,589
    We use rector seal, the yellow slop, #5 I'f I remember right. Teflon is against gas code I thought? 15 psi should be easy to hold, it's Probably a minor issue someone forgot to tighten something maybe.

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