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Thread: Pressure Testing for Leak Detection

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    Pressure Testing for Leak Detection

    I have a gunite pool/spa. I have a leak and have narrowed it down to the spa pressure line. I have some equipment that I can use to pressure test the lines. The question is whether I will need some geophones or other listening device to hear the leak. The leak will almost certainly be under a concrete/pebbled patio. I have read on the forum that listening for a leak through concrete can be difficult. Any help would be appreciated.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Re: Pressure Testing for Leak Detection

    Sometimes you can hear a leak underground just by listening, especially if you alternate testing with air and then water. It's worth trying. If you need additional help, there are services that specialize in leak detection.

    Example
    http://www.americanleakdetection.com/ma ... merica.php

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    Re: Pressure Testing for Leak Detection

    Thanks for the info James, I did read elsewhere also that you could sometimes hear the leak trough the concrete. I did check on american leak detection and their reviews on yelp. Also read about an instance when they pinpointed a leak, homeowner dug up the spot and no leak was there.

    Quote Originally Posted by JamesW
    Sometimes you can hear a leak underground just by listening, especially if you alternate testing with air and then water. It's worth trying. If you need additional help, there are services that specialize in leak detection.

    Example
    http://www.americanleakdetection.com/ma ... merica.php
    dug
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

  4. Back To Top    #4

    Re: Pressure Testing for Leak Detection

    I think that it's worth trying to see if you can hear the leak. As far as services go, they can be quite variable depending on whom you get. Some will be good, and others, not so good. Checking references can be helpful. Asking for some sort of guarantee can help, too. Also, you could ask the service to show you how they determined where the leak is.

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    Re: Pressure Testing for Leak Detection

    Unfortunately the service people in my area have no reviews. Do you happen to know anyone in the Dallas area? Thanks

    Quote Originally Posted by JamesW
    I think that it's worth trying to see if you can hear the leak. As far as services go, they can be quite variable depending on whom you get. Some will be good, and others, not so good. Checking references can be helpful. Asking for some sort of guarantee can help, too. Also, you could ask the service to show you how they determined where the leak is.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Re: Pressure Testing for Leak Detection

    I am not familiar with the Dallas market. However, I would think that it would be a fairly large market for pool and/or leak detection services. Checking review sites like yelp are a good start. Perhaps other sites like BBB, Angie's list etc. would be helpful.

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    Re: Pressure Testing for Leak Detection

    Thanks James. Couldn't find it myself by listening or with the limited detection equipment I had. Pool guy was here for four hours and thought he found it in the spa pressure jets (water was leaking around the outlets). Told him I was losing much, much more water with the motor on so seemed to indicate a line leak. Tested last night and still had a lot of loss even though we had rain.

    Does anyone know how long a line should be able to hold pressure? Pool guy says it will always lose pressure over time (which doesnt make sense).

    Quote Originally Posted by JamesW
    I am not familiar with the Dallas market. However, I would think that it would be a fairly large market for pool and/or leak detection services. Checking review sites like yelp are a good start. Perhaps other sites like BBB, Angie's list etc. would be helpful.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Mod Squad Bama Rambler's Avatar
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    Re: Pressure Testing for Leak Detection

    Theoretically it should hold pressure forever if it's sealed properly, however, practically it will fluctuate with temperature. A plumbing system is considered leak free if it holds pressure 24 hours when filled with water. If it loses more than a few psi it's leaking.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Pressure Testing for Leak Detection

    Thanks Bama. My guy said pressure could reduce to near 0 after 24 hours (which is what it did for me). My guy gave emailed me and gave up. So back to square one I guess.

    Quote Originally Posted by Bama Rambler
    Theoretically it should hold pressure forever if it's sealed properly, however, practically it will fluctuate with temperature. A plumbing system is considered leak free if it holds pressure 24 hours when filled with water. If it loses more than a few psi it's leaking.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Re: Pressure Testing for Leak Detection

    Do the returns have venturi or other air intakes? If yes, that can make testing more difficult.

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    Re: Pressure Testing for Leak Detection

    Thanks. Yes they do have air intakes. Would that make the process of detection using a pressure test and a listening device more difficult? I assumed it wouldn't matter since the constant pressure would cause a steady stream of air to leak from the pipe - and the air leak is what you are listening for.
    Quote Originally Posted by JamesW
    Do the returns have venturi or other air intakes? If yes, that can make testing more difficult.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Re: Pressure Testing for Leak Detection

    It makes it more complicated and difficult. The lines can be difficult to properly plug.

    I find that the leak will most likely be related to where the air line connects to the return line. If you can get the ground saturated with water, and the pipe full of water, then the sound will be louder due to air and water hissing out of the crack, and bubbling through the ground water. Also, having the ground saturated will make it a better conductor of sound.

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    Re: Pressure Testing for Leak Detection

    Thanks, that makes perfect sense. Was talking to another company about pressure testing and this is what he said "pressure test with air only. We pressure test a line for 1 to 2 minutes. If there is a leak, pressure testing will show the leak right away."

    Do you think 1-2 minutes of pressure testing is sufficient to determine whether a line is leaking? Thanks again.

    Yes all lines are separately tested.. Air only.. water bleeds off to slow...
    We pressure up line for 1 to 2 min.. If there is a leak, pressure testing a
    line with air will show the leak right away...
    Quote Originally Posted by JamesW
    It makes it more complicated and difficult. The lines can be difficult to properly plug.

    I find that the leak will most likely be related to where the air line connects to the return line. If you can get the ground saturated with water, and the pipe full of water, then the sound will be louder due to air and water hissing out of the crack, and bubbling through the ground water. Also, having the ground saturated will make it a better conductor of sound.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

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    Mod Squad Bama Rambler's Avatar
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    Re: Pressure Testing for Leak Detection

    Personally I don't think 1 to 2 mins is even close to being enough. About it would tell you is if there was a major blowout.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Pressure Testing for Leak Detection

    Thanks, that's what I was thinking and was the reason I asked the question. My tests showed it holding for an hour but there was a good amount of water still in the line (so I wanted to confirm).

    I'm doing the bucket test again since my last leak detector (although not finding the line leak) claims he did find a like around the spa pressure jets.


    Quote Originally Posted by Bama Rambler
    Personally I don't think 1 to 2 mins is even close to being enough. About it would tell you is if there was a major blowout.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

  16. Back To Top    #16

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    Re: Pressure Testing for Leak Detection

    You cannot pressure test a line with a combination of air and water. You either have to test with water only or blow the water out and use air. But if you truly have a leak testing with air within a minute or two you will know.
    Over 30 years in the pool business
    We build vinyl, fiberglass, stainless steel pools
    Certified in Hydraulics

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    Re: Pressure Testing for Leak Detection

    Thanks for the response. I seem to be getting a lot of conflicting info. Would I know in a minute or two if it was a pinhole leak? Any idea on how many pounds of pressure you would lose on a pinhole leak after one minute? I'm just wondering whether this would be registerable on the gauge.

    American Leak Detection indicated that they pressure test each line for 20 minutes.

    Quote Originally Posted by swimcmp
    You cannot pressure test a line with a hof air and water. You either have to test with water only or blow the water out and use air. But if you truly have a leak testing with air within a minute or two you will know.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

  18. Back To Top    #18

    Re: Pressure Testing for Leak Detection

    Quote Originally Posted by swimcmp
    You cannot pressure test a line with a combination of air and water. You either have to test with water only or blow the water out and use air. But if you truly have a leak testing with air within a minute or two you will know.
    The main reason I suggested mixing air and water was to increase the sound of the leak. However, there is no reason that mixed air and water cannot be used for testing.

  19. Back To Top    #19

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    Re: Pressure Testing for Leak Detection

    Now I am totally confused. I would think there would be consistency in the industry. In this case, one is right (test only air or air & water is ok to test) and one is wrong. I have no idea which is correct.

    Quote Originally Posted by JamesW
    Quote Originally Posted by swimcmp
    You cannot pressure test a line with a combination of air and water. You either have to test with water only or blow the water out and use air. But if you truly have a leak testing with air within a minute or two you will know.
    The main reason I suggested mixing air and water was to increase the sound of the leak. However, there is no reason that mixed air and water cannot be used for testing.
    Jim
    15k inground pool/spa
    3/4hp Whisperflow
    Cartridge filter (Hayward)
    Boostapal: http://www.boostapal.com/

  20. Back To Top    #20

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    Re: Pressure Testing for Leak Detection

    Per Anderson Mfg. air and water cannot be compressed to pressure test. They can be combined to verify a suspected leak.
    Over 30 years in the pool business
    We build vinyl, fiberglass, stainless steel pools
    Certified in Hydraulics

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