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Thread: Air in pump basket

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    Air in pump basket

    Topic split from this thread air-in-pump-basket-t19261 by moderator for better response

    I have what I believe is a simular issue but want clarification. With pump running I can shine a flashlight (night time is easier to see) into the pump basket lid and I see "Champaign" bubbles. Is that caused by the pump action and churning of the water or is that an official air leak? I never have any air at the filter air bleed valve nor do I have air bubbles coming from the returns.
    10,500 gallon IG viking ceramic/fiberglass, 150 GPH cartridge filter

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    Mod Squad Bama Rambler's Avatar
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    Re: Air in pump basket

    If what you're seeing is truly air bubbles you may have a small suction side leak. The first thing I'd try is lubing the pump basket lid with silicon o-ring lube and see if that helps. Also check to make sure the skimmer(s) aren't creating a vortex and sucking a small amount of air in.
    Dave J. TFP Moderator
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    Re: Air in pump basket

    watch those bubbles as you turn the pump off. If they instantly disappear, its cavitation, and you don't have a leak. What is happening is the pump can't get the water it needs/wants.
    Here is a geek discription.
    http://www.google.com/search?hl=en&r...e&ved=0CAYQkAE
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    Re: Air in pump basket

    watch those bubbles as you turn the pump off. If they instantly disappear, its cavitation,
    According to that explanation link, I'm not sure cavitation occurs inside the pump basket. They seem to think it occurs right at the impellor, hence the potential for damage to the impellor if it (cavitation) is allowed to remain for an extended period.
    Dave S. - Forum owner
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    Re: Air in pump basket

    Quote Originally Posted by Pool Clown
    watch those bubbles as you turn the pump off. If they instantly disappear, its cavitation, and you don't have a leak. What is happening is the pump can't get the water it needs/wants.
    Here is a geek discription.
    http://www.google.com/search?hl=en&r...e&ved=0CAYQkAE

    They disappear to my knowledge only because the water level in the backet area drops to the point that it is below the lid seal area (is that normal?)

    Thanks,

    Ken
    10,500 gallon IG viking ceramic/fiberglass, 150 GPH cartridge filter

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    Mod Squad Bama Rambler's Avatar
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    Re: Air in pump basket

    No, that's not normal. After several minutes of running there should be no (or a very small bubble) of air in the basket housing. Sounds like the lid seal is leaking. Lube it up and see if that helps the problem.
    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
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    Re: Air in pump basket

    Quote Originally Posted by Bama Rambler
    No, that's not normal. After several minutes of running there should be no (or a very small bubble) of air in the basket housing. Sounds like the lid seal is leaking. Lube it up and see if that helps the problem.


    Not sure I understand that. How could you have a small bubble, I mean with the force that water is sloshing around in that basket area how could one small bubble stay intact? I could see having one small bubble that sits in the center of the basket area just under the lid with the pump off. However once that pump starts I cannot see how that one bubble survives. Maybe that one normal bubble gets all churned up and breaks up into thousands of tiny bubble which is what I am seeing????
    10,500 gallon IG viking ceramic/fiberglass, 150 GPH cartridge filter

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    Mod Squad Bama Rambler's Avatar
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    Re: Air in pump basket

    My lid has a small circular boss molded in the center and will sometimes hold a small bubble of air for a good long time. Eventually it will go away but sometimes not for a long time.

    Since you're seeing bubbles constantly I still suspect an air leak.
    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
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    Re: Air in pump basket

    Quote Originally Posted by duraleigh
    According to that explanation link, I'm not sure cavitation occurs inside the pump basket. They seem to think it occurs right at the impellor, hence the potential for damage to the impellor if it (cavitation) is allowed to remain for an extended period.
    Dave, you are correct, true cavitation cannot normally be seen in the pump basket. The bubbles only exist where the pressure is low enough to support water vapor which is usually above 29" hg and that can only occur at the impeller. The bubbles will typically form near the impeller inlet and then collapse at the impeller exit, only existing inside the impeller. This is where most of the damage occurs. Youtube has a few videos showing how the bubbles only exist around the impeller.

    However, because the suction is so high when cavitation occurs, it is normally accompanied by an air leak which is why it is often confused with cavitation.

    Also, a couple of really good articles on cavitation:

    http://www.pumped101.com/cavitation.pdf
    http://www.pumped101.com/bubbles.pdf
    Mark
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