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Thread: Low Pump Pressure

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    Low Pump Pressure

    I have a 20,000 in ground gunite pool. There are three returns (two to spa and one to main pool) and three coming back to the pump (main drain, skimmer and cleaner) I have an Aquarite salt generator and heat pump. Pool is 4 1/2 years old. Pump is a Hayward Super II 2HP with a Hayward cartridge filter.

    Everything was fine until a couple weeks ago when I noticed the pressure dropped from 20 lbs to 10 pounds and the filter basket did not fill compeltely and there is about 2 inches between the water level and the basket lid.. It does not mater which if I use the main drain, skimmer or cleaner, the pressure does not move off of 10 PSI and the filter basket is not filling completely with water and there seems to be about 2 inches of air in the filter at the pump. I have replaced the o-ring and that did not solve the pressure problem.

    Any ideas?
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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    spishex's Avatar
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    Re: Low Pump Pressure

    Cleaning your filter should be step 1.

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    Re: Low Pump Pressure

    Welcome to TFP!

    8000 gallon 20' x 48" round vinyl frame pool, 12" sand filter (don't have the specs on the pump), TF100 test kit
    Handy Links: PoolMath, TF-100 Test Kit, Pool School, CYA-Chlorine Chart
    "Shock" is a process, not a product!

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    Re: Low Pump Pressure

    Thanks for the welcome!

    Sorry I forgot to add that I also changed the cartridge filter. A friend has said it might be a clogged impeller?
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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    mas985's Avatar
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    May 2007
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    Re: Low Pump Pressure

    Low pressure can be a symtom of a clogged impeller but usually not with air in the pump basket. That is normally due to a suction side leak. Combined with the low filter pressure, I would guess that there is probably a blockage somewhere in your suction line. It is probably worth checking the impeller but if you don't find anything, then it is probably a blockage.
    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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    Re: Low Pump Pressure

    I had thought blockage at first. However, the low pressure occurs no matter which suction valve I have open (main drain, skimmer or vacuum) and I took apart the Jandy valves and no blockage between the valves and the filter basket at the pump. So unless all three suction lines got clogged at the same time?

    I have a service guy coming today to take a look. It has me baffled to say the least...
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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    Re: Low Pump Pressure

    I guess I should also add, no water loss is associated witht his either. Which is a good thing...I hope.
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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    duraleigh's Avatar
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    Re: Low Pump Pressure

    Look for other air getting into the system somewhere between the intakes (skimmers, drain, etc.) and the pump. That is the suction side of your system. Air is getting into the suction side and not allowing your pump to prime completely.

    Did you check the drain plugs in the Pump strainer basket?

    Look around the valves on the suction side. Sometimes you can hear the hiss as it sucks in air.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Low Pump Pressure

    Service technican came by today. Impeller was partially blocked (grey plastic pieces, kids toy sucked up by vacuum?) pressure immediatly went up. I still have an air leak somewhere on the suction side as there is air in the basket. I will take a look at the valves and drain plugs when I get home later.

    I did notice one thing, where the pipe leaves the pump and heads toward the filter, the soft white material around where the pipe screws into the top of the pump (pipe dope/plumbers putty) is loose. Could air be getting in there?



    One good thing, I watched the service tech so at least next time I know how to take things apart and clean out the impeller if needed
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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    Re: Low Pump Pressure

    Problem Solved Thanks for all the help.

    I did a search and saw where it was suggested to pour a bucket of water over the suction side connections and see if at anytime the air bubbles leave the basket. One by one I eliminated until I poured over the cover to the basket. Bingo, but I was confused, that was the first thing I did was replace the o-ring. Well I took it out and the brand new o-ring had a slight imperfection (crack). I went picked up another and no more air bubble!!!

    Thanks agin for your imput!!!
    South Florida. 20,000 gallons; 16x35 rectangular gunite; Pentair Intelliflo VF Variable Speed Pump; Hayward cartridge; Aqua Rite SWG. Dolphin Oasis Z5 Robotic Pool Cleaner; Kopec 540sc Electric Heat pump pool heater; Pool built in Spring 2004.

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