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Thread: Air in pump

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    Air in pump

    What would cause air in my pump when it turns off? I think I probably have a gap between the gasket and the lid as when the pump turns off a little water comes out. I am thinking this lets air in...I tried lubing the gasket and tightening the lid hard, but it seems every time the pump turns on there is a bit of air in the pump, as soon as its running for 5 seconds there is no air and no leaks of water...Should I replace the gasket or any other thoughts? It seems like both pumps do this. The gaskets look visually good.

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    Re: Air in pump

    What causes it is a leak in the system. If you do not see a water leak when the pump is running, then it is almost always a leak on the suction side.

    However, a suction side leak normally causes air bubbles in the pump basket that you can see when the pump is running.

    There is an article in Pool School about suction side leaks which may help

    Don't overtighten that pump basket lid. Low pressure does more to seal them than screwing them down too tight.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Air in pump

    Thank you, Dave. It seems both pumps are the same way...When the water feature one turns off, it splashes water out under the lid. When the pool pump turns off, it leaks water from under the lid. No water leaks when the pump is running. There are also no air bubbles and the water is solid once the pump fills all the way. That is why I am thinking it is maybe a gasket. Thoughts?

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    Re: Air in pump

    Too confusing for me. Describe one pump at a time and we'll get 'em fixed.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Air in pump

    Dave,
    First pump is pool pump. No detectable leaks. When I turn on the pump there is minimal amount of water in pump. Once it is running for a few seconds, water fills to the top and there are no air bubbles in the pump. However, once I turn it off a little water leaks from under the lid and after awhile air enters the pump.

    Pump two is for a waterfall. Same as pump one that when I turn it on there is minimal water in the pump. However, this one takes longer to get it full even when I add water to the pump before turning it on. Once the pump is running there are bubbles in the water in the pump. In addition, I notice the lid slightly elevates, even though it is screwed down completely. I also notice that the gasket bulges out a bit when it is running. When I turn this pump off water shoots out from under the lid for a second. It is strange how the gasket actually bulges out in one place once it is running...I then took off the lid and resat the gasket and it bulged again when I turned it on.

    I replaced the gaskets in both pumps on Saturday. I lubed them well before putting them in. This resulted in no change.

    Thanks for your help.

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    Re: Air in pump

    Let's work on the pool pump first. If it is leaking water at the O-ring after the pump is turned off, it is likely that O-ring is still the culprit even though you changed it out. I would take the lid off again and inspect everything very carefully to make sure you have the best fit possible. It is NOT important to have the lid on extremely tight......the vacuum created by the pump should make the seal.

    That's by far the most common place for a leak so we have to discover what it is about yours that is not making a good seal. Others may have a good idea to help but, for now, all I can suggest is a careful visual inspection and re-seating it. One thought....is it possible your pump basket lidd or the basket itself has a tiny crack? Could the pump basket lid ever have been warped?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Air in pump

    Dave,
    Thank you. I asked my wife who is home today to check and see if it lays flat. She said it wobbles slightly, but did notice a crack in the waterfall lid. I am hoping a new one fixes that one. Haven't gotten a response about the pool pump lid yet. One more question, would it matter if the basket inside the pump is shorter than it should be? Meaning there is a blue basket/strainer inside the pump of the waterfall to collect debris and it is too short so the water in hole is above the basket instead of lining up perfectly. I don't think this should make a difference, but maybe...

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