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Thread: Pressure Test Results

  1. Back To Top    #1

    Join Date
    Sep 2007
    Location
    Guelph, Ontario, Canada
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    50

    Pressure Test Results

    This weekend, I made my own pressure tester on the weekend which can test for either air or water.

    I tested the return lines with water. They held pressure with a drop from 30 to 29.5psi over 5 minutes.

    When I tested the suction lines with water at the pump, I found an immediate leak where the suction line comes out of the concrete. I was able to temporarily fix this with a piece of rubber and hose clamp.
    When testing again, I still have a drop from 30 to 20 psi in two minutes. I have checked my tester and above ground pipe including temporary fix with soapy water, but found no leak. I tested the suction line again with air to listen for air leak, but I could not hear anything.

    The suction line from the pump has a 3 ft drop from the pump in the first 12ft of run, and an additional 25 ft under the concrete pool deck. I tried to estimate how far down the line the leak is by letting the pressure drop to zero and measuring how much water it takes to refill the pump reservoir. It took just over 9 litres of water to refill. Given the cross section of 1.5 hose, I estimate the leak about 26’ down from the pump (I recognize this is a very rough estimate, but should be good enough to say the leak it is very much under my concrete deck). From photos I took photos during construction of the pool, my suction plumbing has a single line down most of its length from the pump with a ‘T’ just before the skimmer to split between the skimmer and an in wall vacuum port.

    My pump is functioning fine, and since I temporarily fixed the first leak, I no longer see any bubbles in my pump reservoir, and the water doesn’t ‘gurgle’ out of the line when I turn the pump off.
    I have a couple questions
    1) Is 30psi appropriate for this test?, or Should I measure at a lower pressure?

    2) Is the pressure drop in the suction line significant enough to cut the concrete and fix?

    3) Would a stethoscope on the concrete allow me to listen for the air leak?

    4)I have had problems with my liner lifting in the deep end.
    Is there any chance that this leak is related to my lifting liner?
    Carl Schnurr
    96,000 litre inground, vinyl liner, 1 HP 1speed pump, sand filter, Aqua-rite SWG, Hayward Ultra Vac, installed 2005

  2. Back To Top    #2
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
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    Re: Pressure Test Results

    If you use water instead of air, you can see where the leak is if there is one. Usually, you can get get close to 35 PSI at a hose bib or even higher. You just need to plumb the correct fittings to connect the hose. I used 35 PSI water when I pressure checked my plumbing and could immediately determine where the leak was but that was when all the plumbing was exposed. If it is buried, it may be a bit harder to see.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater, ThePoolCleaner

  3. Back To Top    #3

    Join Date
    Feb 2008
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    Flower Mound, TX
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    Re: Pressure Test Results

    Wonder if one could rent one of those cameras like the plumbers use to ID the leak location? It's simply a fiberoptic camera with graduated measurements on the line and a monitor to plug into.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  4. Back To Top    #4

    Join Date
    Mar 2007
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    Coastalish 'down easter'
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    Re: Pressure Test Results

    Something to make sure of is that the plugs themselves aren't leaking while testing, nor the pressure test 'rig' itself!

    We usually use 10 - 15 psi when testing with water, leaks are evident within a minute - but we only know that the line is bad, not where the leak is, unless it's above ground. We use 'geophones' to try to isolate the leaking area, but they are 'hit and miss'

    What is the plumbing made of? There are certain places more likely to leak, depending on the plumbing pipe.

    Keep us posted and we'll add more to help you find the leak
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  5. Back To Top    #5

    Join Date
    Sep 2007
    Location
    Guelph, Ontario, Canada
    Posts
    50

    Re: Pressure Test Results

    Thanks for the response.

    I checked out my pressure tester by using my pool plugs. The plugs failed around 15 psi.
    When I rechecked my suction line, it also failed at 15psi. I'm going to try some red phenol around the plugs while under pressure. If I'm still uncertain if I have a leak, I'll use some rubber stopper style plugs. For some reason the plugs held while testing the return lines.

    I also learned a couple things troubleshooting my tester. It is difficult to test with air unless I can remove air entirely from the line. Since my skimmer is lower than my pump, that's difficult to do without lowering the pool water. So I'm not sure I even have a leak anymore as I already temporarily fixed the one.

    I thought I'd attach a photo of my pressure tester for comment/improvements.
    I have an air valve stem to do air testing, a valved garden hose, and a pressure release/bleed valve to remove air from the system. On the other end I have made attachments to connect to my 2" union thread on my return line from my salt cell to test return lines, and
    1.5" union thread on my suction line from my pump. When I joint 1.5" union together I can validate my tester with my pool plugs.
    Carl Schnurr
    96,000 litre inground, vinyl liner, 1 HP 1speed pump, sand filter, Aqua-rite SWG, Hayward Ultra Vac, installed 2005

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