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Thread: Pumps looses Prime

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    Pumps looses Prime

    My 1 HP North Star pump looses prime when it turns off for the day. What should I look for as a problem?
    Inground Grecian 20,000 gallons vinyl liner
    Hayward 250 BTU Propane heater
    Hayward DE Filter
    1 HP Northstar Pump
    Spill Over Spa

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    Guest
    your sucking air someware and its enough to make you loose prime

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    I think that Rollin Thunder has hit upon the problem. I assume that the pump is above water level, if so the air entering the system will allow the water to drain back into the pool. There is a chance that it's the lid on the Northstar - do you see a gush of water coming out of the lid when the pump turns off? It is possible that the lid isn't fully sealed with the pump off (they only fully seal when the pump is running [as an aside - if you have trouble removing the lid, try loosening it when the pump is running ] ) If you are unable to find any other source, you can install a 'check valve' (a one way valve that lets water only flow into the pump and closes when the pump is off to preserve the prime) - if you go this route, be sure to get one with a union, so you can still blow out the lines for the winter.

    HTH - waste 8)
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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    Yes a gush a water comes out when the pumpd shuts off, but it has been doing that all season. The pump started loosing prime just this past wednesday. I will take the lid off and put it back on.
    Inground Grecian 20,000 gallons vinyl liner
    Hayward 250 BTU Propane heater
    Hayward DE Filter
    1 HP Northstar Pump
    Spill Over Spa

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    I took off the cover and put it back on again and it did not loose prime over night. I will have to keep an eye on it.

    What about the fact that it gushes out water all summer when the pump turns off and not having a problem until last week?
    Inground Grecian 20,000 gallons vinyl liner
    Hayward 250 BTU Propane heater
    Hayward DE Filter
    1 HP Northstar Pump
    Spill Over Spa

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    JasonLion's Avatar
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    That depends on what you mean when you say "gushes out water". The filter is presurized while the pump is running, so some outflow should be expected when the pump goes off. If all of the air is vented from the filter this will be minimized, but will still happen at least a little. All of which is seperate from losing prime.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    sammm's Avatar
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    Quote Originally Posted by sunnydays
    I took off the cover and put it back on
    Are you talking about the cover on the small basket in front of the pump? Is there an O-ring on the cover? If so, try lubing it with some pool/spa type lube.
    WetEdge Satin Matrix, 16K gallon, Pentair NSP-60 DE filter, Pac Fab Challenger, 2HP pump, BBB, Polaris 360

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    Yes that is the cover I am talking about. I will add some lube to the O ring when I get a chance.
    Inground Grecian 20,000 gallons vinyl liner
    Hayward 250 BTU Propane heater
    Hayward DE Filter
    1 HP Northstar Pump
    Spill Over Spa

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    With the Northstars you also have to be sure that the pump basket is fully down or the lid doesn't seal correctly.
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  10. Back To Top    #10

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    I will look at that as well when I open it up again.

    Thanks for all you help!!
    Inground Grecian 20,000 gallons vinyl liner
    Hayward 250 BTU Propane heater
    Hayward DE Filter
    1 HP Northstar Pump
    Spill Over Spa

  11. Back To Top    #11
    mas985's Avatar
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    Quote Originally Posted by sunnydays
    What about the fact that it gushes out water all summer when the pump turns off and not having a problem until last week?
    Mine does that sometimes too. I think it is pretty normal for Northstars when the pump shuts off.
    Mark
    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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