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Thread: Cavitation? Air? Trouble ...

  1. Back To Top    #1

    Join Date
    May 2014
    Houston Area

    Cavitation? Air? Trouble ...

    Hello and thanks for reading this. I have an older Hayward system (I didn't build it) and I think I might have a problem. The pump basket (image 1) shows a lot of swirling, the filter housing collects air (after completely draining the air, it takes just a few minutes for some air to re-collect). The psi is around 4, no air bubbles in the pool, system primes itself just fine and seems to hold suction when turned off. I noticed two the pipe connections on the bottom of the skimmer, but they are quite small, maybe an inch each and one doesn't have any suction.

    It looks as if the pump would just not get enough water. And I was wondering why there are two pipe 'holes' on the bottom of the skimmer with only one actually sucking water.

    Any hints are appreciated.


  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Cavitation? Air? Trouble ...

    They symptoms you describe suggest air is getting into the plumbing somewhere on the suction side of the pump.

    Skimmers with two holes are fairly common, though often one hole is blocked off. When both are open the second one often leads to the main drain.

    The most common causes of air getting into the plumbing are: low water level allowing a vortex to form that draws air into the skimmer and the pump strainer basket lid not dealing properly. It is also possible that it is because of a leak somewhere that draw in air when the pump is producing suction.

    In any case this isn't cavitation, which is exceptionally noisy and would not let air into the filter.
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  3. Back To Top    #3
    mas985's Avatar
    Join Date
    May 2007
    Pleasanton, CA

    Re: Cavitation? Air? Trouble ...

    Welcome to the forum

    1) Air in the pump basket just means there is an air leak, not cavitation.

    2) Skimmer should have only one port that has suction. The other is for a main drain or a wall port.

    3) 4 PSI is very low for that pump unless it is running on low speed.

    4) It is very hard to help when we know nothing about your system so please follow these instructions:
    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

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