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Thread: Suction side leak

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    Suction side leak

    I have bubbles in my pump strainer basket and when I shut off the pump there is tremendous back pressure that blows the lid off the skimmer basket. The only way to avoid this is to bleed off the air at the filter prior to shut down. I'm running the pump motor 24/7 for fear that it will not prime properly at start up.

    I have replaced the o-ring on the lid and I have also swapped lids with a parallel unit running the in-ground cleanning system (no bubbles in this basket) but no improvement. I also just replaced the motor itself (not sure what happened but may have been related to a power failure) and changed out all the seals and gaskets on the pump in the process.

    Water level at the skimmers is good but the skimmers seem to be tied to the cleaning system anyway so I think my pump is just drawing water from the main drain. There are some small drips of water coming from pipe joints after the pump - could this be the problem or where else would I look? I know this issue has been covered in other threads but appreciate any help that can be offered for my situation.
    30,000 gallon IG
    Sand Filter
    2 HP Pentair Whisperflo pump/motor
    IntelliChlor chlorine generator

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    Re: Suction side leak

    YOur sytem is sucking air somewhere between the skimmers and the impeller.....after the impeller, the water is pressurized and air can't get in.

    They are often VERY hard to find but find that leak(s) and the air will stop. Did you check the drain plug(s) at the bottom of the pump basket?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Suction side leak

    I had not ... there are two drain plugs and I just now put some silicone around the seals while the pump was running but this did not show any change with the bubbles in the strainer basket. I could empty the pump and remove/replace the plugs if you think this might be the problem.
    30,000 gallon IG
    Sand Filter
    2 HP Pentair Whisperflo pump/motor
    IntelliChlor chlorine generator

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    Re: Suction side leak

    That doesn't sound like that's the source.

    Probably the best way to find the leak is to be very methodical and start with the skimmer and make sure it's not slurping air........once that's done move to the next logical place like a valve or union. Again, not easy, but once you track it down, it's usually a simple fix and you're good to go.

    At some point when the pump is off and basket empty, you should remove the plugs and clean up that silicone. Reinstall the plugs using about 3 wraps of teflon tape and snug them down just a little more than hand tight.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Suction side leak

    it is most likely the pump lid o ring or the o rings in a valve on the suction side.

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    Re: Suction side leak

    I have a Pentair CVA-24T valve actuator ... would I find the valve o-rings inside this unit? I've already replaced the o-ring in the pump lid.
    30,000 gallon IG
    Sand Filter
    2 HP Pentair Whisperflo pump/motor
    IntelliChlor chlorine generator

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    Mod Squad Bama Rambler's Avatar
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    Re: Suction side leak

    The o-rings are in the valve not in the actuator itself.
    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

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    Re: Suction side leak

    One more dumb question before I replace the o-rings in the diverter valve ... since my pump is below the level of the pool won't water flow when I remove the valve? Thanks for all the help so far.
    30,000 gallon IG
    Sand Filter
    2 HP Pentair Whisperflo pump/motor
    IntelliChlor chlorine generator

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    Mod Squad Bama Rambler's Avatar
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    Re: Suction side leak

    Yes it will. You need to plug the plumbing either in the pool or between the pool and the valve.
    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

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    Mod Squad jblizzle's Avatar
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    Re: Suction side leak

    Yup. You will likely need try to plug whatever lines run to the the valve you are opening. And close off the return side valves if you do not have any check valves in place.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Suction side leak

    Just a follow up ... replacing the o-rings on the Jandy valve solved my problem (no more air bubbles in the pump strainer basket and no more back pressure when shutting off the pump). Thanks to everyone for their help. I did notice that there was a plastic collar (sits above the two o-rings on the valve) that was cracked but I just put it back on the stem since there was no repalcement included in my repair kit. My local pool store said the rubber o-rings do all the work keeping the unit air tight and it doesn't seem to be causing any problems.
    30,000 gallon IG
    Sand Filter
    2 HP Pentair Whisperflo pump/motor
    IntelliChlor chlorine generator

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