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Thread: Possible pump cavitation?

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    Join Date
    Jan 2010
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    Claremont california
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    Possible pump cavitation?

    Hello friends,

    I am experiencing the following symptoms with my intelliflow pump:

    After running the pump for 18 hours, the pump's basquet is almost empty. The pump is set to run at 750 rpms. Pump primes well but slowly the basket starts to drain and only small trickle comes out of the suction end. I know the volume of water sucking should not be a lot due to the 750 rpm speed but some how the pump is almost running in an empty water container. Through the glass container, I can see there is about 4 inches of water in it.


    Please help,
    G.


    Pumpentair intelliflow.
    underground copper pipe 1.5
    above ground pipes 2.00 pvc.
    pool type: 22k plaster with side spa kidney type
    None salt water.

    Two skimmers and two drains one drain in the pool and one in the spa.

    pool location: Claremont California
    22k plaster pool kidney shape. Pentair 4000 de series 48 ft. 2 SKIMMERS, 2 drains (pool and spa), 3 returns (2 pool and 1 spa) gas heater and pentair intelliflow , Underwater pentair light.

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    Texas Splash's Avatar
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    Re: Possible pump cavitation?

    Is it safe to assume you've back-tracked and checked everything as listed on this link?: Pool School - Suction Side Air Leaks
    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
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    Mod Squad jblizzle's Avatar
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    Re: Possible pump cavitation?

    Also, cavitation is not when the pump basket drains of water ... not sure why some many member come here and post that

    Cavitation is when air bubbles are created in the impeller which would not be seen in the basket and the pump would sound like it is full of rocks.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Re: Possible pump cavitation?

    Quote Originally Posted by jblizzle View Post
    Also, cavitation is not when the pump basket drains of water ... not sure why some many member come here and post that

    Cavitation is when air bubbles are created in the impeller which would not be seen in the basket and the pump would sound like it is full of rocks.
    Thanks so very much for the information. I use the term cavitation because this is the only word I knew to describe my problem.

    - - - Updated - - -

    Quote Originally Posted by Texas Splash View Post
    Is it safe to assume you've back-tracked and checked everything as listed on this link?: Pool School - Suction Side Air Leaks
    This was the firs section I looked into. I also was under the impression that the big o ring around my d.e. filter might have been faulty.

    Please advice if you have any tips to address my problem.

    Tnx,
    George
    22k plaster pool kidney shape. Pentair 4000 de series 48 ft. 2 SKIMMERS, 2 drains (pool and spa), 3 returns (2 pool and 1 spa) gas heater and pentair intelliflow , Underwater pentair light.

  5. Back To Top    #5
    Mod Squad jblizzle's Avatar
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    Re: Possible pump cavitation?

    Filter is on the pressure side of the pump and would not cause air in the pump.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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    Join Date
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    Re: Possible pump cavitation?

    Quote Originally Posted by jblizzle View Post
    Filter is on the pressure side of the pump and would not cause air in the pump.
    Thanks for the information.

    I am going to do a see if the incense test. I saw this type of test on youtube. Do you think this sort of test is reliable?

    I welcome any information to deal with this air leak,

    Thank to everyone who has read my post,
    George
    22k plaster pool kidney shape. Pentair 4000 de series 48 ft. 2 SKIMMERS, 2 drains (pool and spa), 3 returns (2 pool and 1 spa) gas heater and pentair intelliflow , Underwater pentair light.

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    Re: Possible pump cavitation?

    I did the water test: Pool School - Suction Side Air Leaks and was not able to find the problem. I saw a video of this test and it looks very easy to find. I spend about 45 minutes trying to look for the air suction but was not able to find it. I relube the following items:
    a) basket cap o-ring
    b)jandy valve covers o-rings
    c) Union Threaded 2in. MPT x 2in. Slip for IntelliFlo pump
    d) lube both drain caps.

    Is there anything else I can do to find this pesky problem?

    Please advice,
    G.
    22k plaster pool kidney shape. Pentair 4000 de series 48 ft. 2 SKIMMERS, 2 drains (pool and spa), 3 returns (2 pool and 1 spa) gas heater and pentair intelliflow , Underwater pentair light.

  8. Back To Top    #8

    Re: Possible pump cavitation?

    If your filter is dirty at all you may want to clean it.

    There is a certain difference between rpm and flow rate that will eventually cause air to form in my pump basket as well.
    The problem is, as head increases (due to filter restriction) flow reduces while RPMs remain the same. So, the impeller essentially slips in the water stream.

    It's difficult to maintain a prime at low rpm especially if there is a difference in height between the pump and pool water levels, and the filter is clogged.

    Obviously, the system is allowing air in or flashing is occurring.

    Also, check for an air leak in the drain plugs. I see you've checked them, but you may have a hair line crack around the plugs.
    24k gallon inground vinyl liner pool, 8'-3' depth, 2 skimmers, 3 returns, basic 5 chem kit.
    Hayward: DE-60 filter, Superpump VS, AquaRite salt chlorinator w/T-Cell 15, TigerShark QC robot. Jacuzzi hot tub ~350gal. Air blower type, w/8 jets.

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