Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 15 of 15

Thread: Leak detective work

  1. Back To Top    #1

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Leak detective work

    I'm having some fun and games with a new (to us) pool and its plumbing....

    Some context: in ground pool, overflow spa. One main drain, two skimmers - diverter at pad.

    We had some work done to replace some of the pool deck, and in doing so some of the pipe work got damaged - primarily the spa & pool returns. I needed to drain the pool below the level of the returns in order to replace the damaged pipe.

    So - in trying to drain the pool via the main drain only I noticed the pump losing prime very quickly. Skimmer only is fine - but as soon as the main suction was diverted in the pump would lose prime again. The prime loss is dramatic and instant - barely a trickle of water.

    This wasn't previously the case - in the fairly recent past I was able to suction just the main.

    I hadn't noticed any water loss - so was assuming an air leak above the water line. I have dug up the obvious candidate locations (joints around the previous damage) but nothing obvious.

    So, I reversed the flow - pumping water down the suction line from the pad, hoping that the reverse pressure from the pool would be enough to force water out of the air leak...but nothing.

    There is one other location (under the deck at the wall by the main drain) that could be it...but given how much water I pumped back down the line I would expect to see some evidence.

    All that, coupled with how vigorously the pump loses prime (I.e. As if here was just an open pipe!) I am wondering if something else is going on.

    Is it possible these symptoms could be of a blocked main drain line? That it isn't sucking air in - but essentially creating a vacuum?

    The drain has a cover of course - but there has certainly been some debris in the pool during the construction work.

    Any thoughts!?


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  2. Back To Top    #2
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    Any chance that MD line tied-in anywhere else underground? Connected to something (sharing a line) that may have been damaged from the decking work? After all, it sounds like all your troubles are related to that project. Blockage? ... perhaps. But if the screen has been in-place, is it likely that something that small could be causing your problems?

    Oh, and silly to ask ... any chance your diverter is not properly set or something?
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  3. Back To Top    #3

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    I have the line exposed pretty much from the pad through the damaged area and don't see any issues (or it being tied in elsewhere).

    I also tried filling all the trenches with water - but no difference. The screen is in place on the drain.

    Quite the conundrum - I guess part of the question is could an air leak be so severe to create instant prime loss and no flow...yet be small enough not to allow any noticeable water egress?


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  4. Back To Top    #4
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    Good question. Others may have personal experience. But I would say from previous suction leaks that air is definitely the toughest to find. And it doesn't take much to drastically effect prime. Normally we'd ask you to rule-out all the suction-side 101 items (pump basket O-ring, drain plug, etc), but your skimmer suction seems to be fine.

    When you tried pushing water backwards, were you able to actually seal it off to increase pressure? Did you have a bladder king or something to seal the water from the pad side? I can see where filling the trenches with water would seem to seal anything exposed in those areas. If you get to where you've exhausted everything visible to you, your next option may be a pressure test to see how long that MD line can hold 20-30 psi of water/air.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  5. Back To Top    #5

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    Good question - it was under some pressure...but certainly not sealed. At the various points of the pipe I have exposed I can hear a water trickle every now and then.

    I also saw the occasional small air bubble coming out of the main drain in this reverse flow configuration.

    A clog buster might be a good next step...


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  6. Back To Top    #6
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    I agree. Start with the simplest (and cheapest) methods first. The one good thing is you should have very good pool circulation with 2 skimmers, so even if you have to keep the MD closed for a while (even indefinitely) it shouldn't effect pool chemistry. Keep us posted. Curious to see how this turns-out.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  7. Back To Top    #7
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    26,699

    Re: Leak detective work

    I am watching to learn!

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  8. Back To Top    #8

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    Slight complication at the moment is that I need to drain the pool below the level of the jets to repair that pipe. Guess I better go get a sump pump!


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  9. Back To Top    #9
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    Rats! Figures right? The one time you could really use that MD.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  10. Back To Top    #10

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    Quick update - I managed to seal the reverse flow...and all it managed to do was start filling the pool via the main drain. At a relatively good rate...with no noticeable leaks.

    I found a pump, so am going to drain it a bit...fix the remaining return to keep the chem in line and keep investigating.


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  11. Back To Top    #11
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    Wow. That's interesting. You wouldn't think one single line could be such a mystery. After you fix the return(s), maybe you'll look back and find something right in front of you that was there the whole time. One can always hope right? But we can't lose track that a reverse "water" flow may not show immediate signs of a problem (leak) quite as fast or easily as air. So if you are sure about all the MD line connections from the drain itself leading-up to the pump, then a gauged pressure test may still be in order.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  12. Back To Top    #12

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    Right...but I think it rules out the idea of a blockage. Need to ponder whether I think that is a good or a bad thing!


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  13. Back To Top    #13

    Join Date
    Mar 2013
    Location
    Houston, TX
    Posts
    18

    Re: Leak detective work

    Latest update. Gave in and called a leak detection company (who were outstanding)

    After a good while he located the leak - under the new deck. He said it sounded like a decent size break based on the speed at which the air escaped under the pressure test.

    Today we jacked the concrete at his mark and found it. Pipe was completely shattered.

    Currently siphoning some water out to get below the pipe, the should be a simple fix.


    25k gal, IG plaster, 2HP centurion pump, Purex Triton DE, overflow spa, zodiac blower

  14. Back To Top    #14
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Leak detective work

    Mystery solved! A bit of a mess now I suspect while things get dug-up and cleaned, but at least now you know. Hope the rest of your season goes much smoother.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  15. Back To Top    #15
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: Leak detective work

    Any idea why the pipe was shattered? are you in one of the geologically active fault zones around Houston?
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •