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Thread: Pump low/no flow while running 24/7

  1. Back To Top    #1

    Join Date
    Jun 2015
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    Raleigh
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    Pump low/no flow while running 24/7

    I'm at my wits end. I have a two year old install, and the pump is losing flow or has very low flow (pump basket emptying). It might run for a few days or it might happen in a few hours. The only way I can maintain flow is to up the RPM's (variable speed Hayward) to around 3000 RPM...Even at 2200 RPM, it will lose prime. And again, i've modified the schedule to run 24/7 to isolate the issue and it is still doing the same, so it's not a matter of losing prime during idle period. The particulars:

    Hayward multispeed Pump - 2 years old
    Sand filter - running 10 PSI during normal operation
    Two main drains (valve wide open) and one skimmer (valve wide Open). I usually proportion the main drain down, but to isolate this problem, I have them both opened
    Return valve wide open

    Flow - Main, Skimmer tee after valves into pump inlet...pump through SWG then through Sand Filter through return

    What I've done:

    Increased speed of pump
    Run 24/7
    Make sure baskets, skimmer are clean
    Made sure Pump Impeller was clean
    Greased basket seal - have new one on order
    Water level is not decreasing so not likely a leak
    No air leaks at fittings on suction side best I can tell
    I don't see air in the returns in the pool

    Each time I find this condition, the pump is running, there's little flow through the basket. As soon as I press speed 4 (3200 RPM), the pump reprimes and I have flow again.

    So my questions:

    1) Would a bad basket seal cause this problem? I have a new one on order, but less than 2 years old, the seal looks fine and rubbery

    2) Is it possible the impeller is damaged?

    3) Anything else I should be looking at? Maybe something in the sand filter, but I'm not seeing any pressure spikes like a plugged return. Going to order a new pressure indicator just to be sure.
    18' x 38' Pool, 3' to 8' Depth
    Vinyl Liner
    SWG
    Variable Speed Pump
    Sand Filter

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    Re: Pump low/no flow while running 24/7

    Try closing the main drain valve and run just the skimmer at different speeds. Check the skimmer weir door to make sure it doesn't hang up. If all okay close the skimmer valve and run just the main drain the same way. One tip I don't no what type suction valves you have but try closing them with pump running and see if there's any air intrusion

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    Re: Pump low/no flow while running 24/7

    Quote Originally Posted by kadavis View Post
    Try closing the main drain valve and run just the skimmer at different speeds. Check the skimmer weir door to make sure it doesn't hang up. If all okay close the skimmer valve and run just the main drain the same way. One tip I don't no what type suction valves you have but try closing them with pump running and see if there's any air intrusion
    I have two ball valves....one from the pair of main drains, and one from the skimmer.

    So, right now, with pump running 3000 rpm, basket is full of water. When I close the skimmer ball valve, I hear water "spraying" (best sound term I can come up with), and I see maybe 20 or so small air bubbles (about the size of a pea) appear in the basket. They dissipate within a minute. If I repeat, the bubbles are less each time. If I do the same on the main drain side, I might see 5 or so bubbles, but doesn't seem as many as on the skimmer side. Water is well above skimmer suction and weir door is operating normally. What do the air bubbles on valve closing mean? According to this thread, it's normal: Bubbles from main drain
    18' x 38' Pool, 3' to 8' Depth
    Vinyl Liner
    SWG
    Variable Speed Pump
    Sand Filter

  4. Back To Top    #4
    Mod Squad pooldv's Avatar
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    Re: Pump low/no flow while running 24/7

    Sounds like there is a suction side air leak. More here about tracking that down, Pool School - Suction Side Air Leaks
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