Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 17 of 17

Thread: pump looses pressure

  1. Back To Top    #1

    pump looses pressure

    Hi everyone,

    have a 30k gallon inground pool with Hayward sand filter; location Phoenix, AZ. Within the last 3 weeks the pump will run about 15 lbs pressure, then back off to 10, then back to 15, ect...After the air enters the line, the pressure drops, until the air comes out the return in the pool bottom, then the cycle continues.

    Air is clearly getting into the system somewhere; here is what has been done, to no avail.

    -All ABOVE ground, intake plumbing,has been replaced up to the round filter with clear lid
    -The round filter, clear lid and o-ring have been replaced, this bolts directly to the pump. O-ring was lubed.
    -the "2 way valve" controlling suction from vacuum and/or skimmer basket replaced
    -new 3/4 hp motor, (same hp as old)
    -new vacuum hose, (old hose segments were cracked)


    When turning the intake valve to 100% skimmer basket suction, (removing suction from the vacuum) the pump still looses pressure, so I'm guessing this is where the problem lies; not the vacuum intake.

    Short of ripping up all underground intake lines, does anyone have suggestions? I REALLY want to get this thing back to pumping 30 lbs pressure like it was last summer.

    thanks!

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: pump looses pressure

    Just a couple of things you may have already checked.

    Is the skimmer creating a vortex allowing it to suck in air?

    Is the skimmer weir operating correctly? Not sticking even a little.

    Is the water level being maintained the same as always? Even a little bit lower level will give some pools a fit!
    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

  3. Back To Top    #3

    Re: pump looses pressure

    No vortex; there isn't near enough suction to create a vortex. Skimmer weir is OK also. Water level is actually higher than normal.

    Since the pump hadn't been running worth a $%$#, we actually had the pool drained today; they will be cleaning, refilling tomorrow as it had turned green. I guess algae does grow @ H2O temps < 60 deg!

    The only other thing I can think of is underground PVC b/t pump - skimmer. There are about 4 PVC lines in a cluster and last fall while planting some plants, I slammed into the lines with a shovel, cracking one of them. I had a handy-man out to fix my foul up.

    After cutting out the broken section, they added a 90 deg. fitting to the pipe to bring the PVC towards the surface, then added 3 more 90 deg. fittings to return the PVC, back to the existing line that ran to the pump.

    Anyway, this is suspect to me, and will probably have them out for inspection work. I've since read about spraying the pipe with water and checking for bubbles....any other comments are appreciated!

    thanks again






    Quote Originally Posted by Bama Rambler
    Just a couple of things you may have already checked.

    Is the skimmer creating a vortex allowing it to suck in air?

    Is the skimmer weir operating correctly? Not sticking even a little.

    Is the water level being maintained the same as always? Even a little bit lower level will give some pools a fit!

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: pump looses pressure

    Sounds like a pretty good sized leak. I hope it's not hard to find.
    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

  5. Back To Top    #5

    Re: pump looses pressure

    could I plug the skimmer intake and vacuum intake, then fill the lines with water, (garden hose) from the pump side, then un-earth and look for water leaks?

  6. Back To Top    #6
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: pump looses pressure

    Do you still get air when set to draw 100% from the vacuum port?
    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

  7. Back To Top    #7

    Re: pump looses pressure

    Quote Originally Posted by Bama Rambler
    Do you still get air when set to draw 100% from the vacuum port?
    I can't tell whether it's getting air, or not capable of drawing enough water through the small intake on the barracuda. Guess I'd have to take the vacuum off and hold the hose under water...

  8. Back To Top    #8
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: pump looses pressure

    That'd be my first test. If the vacuum port doesn't draw air at least you know it's in the skimmer line.
    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

  9. Back To Top    #9

    Join Date
    Dec 2010
    Location
    San Diego, CA
    Posts
    1,129

    Re: pump looses pressure

    Quote Originally Posted by pecker88

    After cutting out the broken section, they added a 90 deg. fitting to the pipe to bring the PVC towards the surface, then added 3 more 90 deg. fittings to return the PVC, back to the existing line that ran to the pump.
    Why was that done?
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

  10. Back To Top    #10
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: pump looses pressure

    Quote Originally Posted by carlscan26
    Why was that done?
    Whatever the reason it was done, it wasn't a good idea, though it isn't the end of the world either. My guess is that they couldn't figure out how to connect a straight piece of pipe. There isn't much give in PVC so you need a special slip fitting and have work very quickly to connect in a short straight section. By turning 90 degrees a couple of times you create some extra give in the pipe and gain the freedom to work more slowly and with only standard fittings.

    pecker88, shaving cream is good for spotting air leaks. You can see it getting sucked into the pipe. You can also use a garden hose and watch for air to stop coming into the pump strainer basket when you are running water over the area with the leak. With a garden hose you need to move slowly, as it can take a moment for the existing air to clear out once the leaking spot starts getting water on it.

    Since you have a valve, you can either locate the leak, or isolate it to one section of underground plumbing. Check if you get air with the valve set to 100% vacuum, and if you get air with it set to 100% skimmer. If one of those stops the air then the other section of pipe is bad. If both settings still have air then the leak is between the valve and the pump. For leaks between the valve and the pump, the garden hose or shaving cream approach should locate it.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  11. Back To Top    #11

    Re: pump looses pressure

    Quote Originally Posted by JasonLion
    Quote Originally Posted by carlscan26
    Why was that done?
    Whatever the reason it was done, it wasn't a good idea, though it isn't the end of the world either. My guess is that they couldn't figure out how to connect a straight piece of pipe. There isn't much give in PVC so you need a special slip fitting and have work very quickly to connect in a short straight section. By turning 90 degrees a couple of times you create some extra give in the pipe and gain the freedom to work more slowly and with only standard fittings.

    pecker88, shaving cream is good for spotting air leaks. You can see it getting sucked into the pipe. You can also use a garden hose and watch for air to stop coming into the pump strainer basket when you are running water over the area with the leak. With a garden hose you need to move slowly, as it can take a moment for the existing air to clear out once the leaking spot starts getting water on it.

    Since you have a valve, you can either locate the leak, or isolate it to one section of underground plumbing. Check if you get air with the valve set to 100% vacuum, and if you get air with it set to 100% skimmer. If one of those stops the air then the other section of pipe is bad. If both settings still have air then the leak is between the valve and the pump. For leaks between the valve and the pump, the garden hose or shaving cream approach should locate it.
    your correct, they used standard fittings, so when a section is cut out, with little 'play' in the pipe, (it goes next to wall, under wall, next to sidwalk) no way to get new sec. of pipe between the couplers.

    we hooked a garden hose pressure test device, (w/ guage) up to the skimmer line and filled it to ~30 psi.It held for about a second, then lost all pressure. They dug up all the lines they could, before it goes under 10-15 feet of pool decking, and saw no leaks. Given how quickly the pressure went down, it had to be spraying out somewhere, and we saw nothing.

    pool guy said skimmer baskets commonly spring leak where pipe connects...dunno. Short of a jack hammer, I'm lost. Going to call in the pro's for an estimate.

    stay tuned!

  12. Back To Top    #12

    Re: pump looses pressure

    well, the "pro's" must be busy; our weekly pool guy supposedly can't find anyone to do the repair. Gotta love someone who can't do 1 extra minute of work w/out extra $$.

    Brainstorming, I thought of something...
    Given the correct type of flexible 1" to 1.5" hose, could I simply use the existing 2" PVC as 'conduit'? I would shove the flexible hose down the 2" line all the way to the pump. All the underground PVC is currently exposed, except for the 10 ft or so that runs under the pool decking. Given a snag-up, I could simply cut the 2" line and gain access to the flex. hose and pull it the rest of the way.

    Once the flex. hose gets to the pump, I'd saw off the 2" line, and simply hook up the hose. Water would not run out of the now sawed off 2" line because it's well above the water line. The flex hose would be flush with the bottom of the skimmer.

    While this would obiv. have reduced capacity, it would run w/out air leaks...

    Opinions??

  13. Back To Top    #13
    Melt In The Sun's Avatar
    Join Date
    Oct 2009
    Location
    Tucson, AZ
    Posts
    3,899

    Re: pump looses pressure

    You could do that, but the line would be too small to give you good performance. You also would still be losing water out of wherever the leak is.

    As much as it sucks, I think a jackhammer is the answer.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

  14. Back To Top    #14

    Join Date
    May 2007
    Location
    South Central NJ
    Posts
    3,192

    Re: pump looses pressure

    How far is the skimmer to the nearest deck edge?

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  15. Back To Top    #15
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,482

    Re: pump looses pressure

    Quote Originally Posted by pecker88
    I REALLY want to get this thing back to pumping 30 lbs pressure like it was last summer.
    Was it really running at 30 PSI? That is not normal nor desired and would indicate a significant return side blockage especially for a 3/4 HP pump. You may have issues with the suction side but if you were operating at 30 PSI, then you have issues with the return side as well. But maybe with all the changes you fixed that issue or perhaps you had a bad filter gauge.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  16. Back To Top    #16

    Re: pump looses pressure

    I guess it wasn't quite 30psi last summer; prob. closer to 25. Regardless, when the water falls were on, they gushed out water. Now, it's a significant, noticeable reduction of water coming out the falls.

    Re: the "line that's leaking air would still continue to leak water"...I don't think it's leaking that much water. It only seems to suck air when the pump builds pressure to around 12 psi, then the leak lets air in. When the air bubble gets to the pump, the pressure drops to the point where the leak is almost un-noticeable. This causes pressure to start rising, to the point where the leak lets air in, and the process continues.

  17. Back To Top    #17

    Re: pump looses pressure

    Quote Originally Posted by PoolGuyNJ
    How far is the skimmer to the nearest deck edge?

    Scott
    ~1.5 ft, but...at the edge of the decking is a cinder block, stucco'd wall; property line. The pvc runs under the decking for about 10 ft, then I assume makes a 90 deg. turn and meets the bottom of the skimmer.

Posting Permissions

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