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Thread: Pump partially losing prime

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    Pump partially losing prime

    POOL SETUP:

    12,500 Gallon Marcite Pool
    Hayward Max-Flo II Pump
    Hayward Sand Filter
    Hayward Salt Chlorinator
    Equipment replaced and resurfaced March 2010.


    POOL SCENARIO:

    I recently discovered my pump is losing partial prime every 15-20 seconds. The leaf basket water level drops to about half, then slowly refills. The process repeats about 10 seconds later. The return jets constantly produce a large number of air bubbles. I have replaced the leaf basket gasket, inspected and silicone lubricated the O-ring in front of the pump. I have tested for leaks on the suction side by running a hose over every above ground connection and using shaving cream. I have turned the pump on and off to see if water leaks from anywhere but nothing. I now suspect it is a broken pipe below ground. I have one pipe from the pump leading below ground.

    Can this possible be anything other then a broken pipe below ground? Such as pump seal, clogged line, etc?

    I have not been running the pump since this problem for fear of burning out the pump, as such the pool is now green. I have contacted a leak detection company but they will only pressure test the line and not do a through inspection until the pool is clear. Can I safely run the pump in this fashion without damaging it? Are there any other tests I can run to help determine if a break exists and where?

    Any suggestions or thoughts would be appreciated.

    Kevin

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump partially losing prime

    Have you checked the skimmer & weir to make sure it's not creating a vortex and to make sure the weir isn't sticking even a little bit?

    You could run a temporary suction from the pool to the pump and see if that fixes 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
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Pump partially losing prime

    I visually checked the skimmer and weir while the pump was running and no air is getting sucked from the the skimmer entry point. Can you explain how to setup a temporary suction from the pool to pump.

    Thanks,
    Kevin

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump partially losing prime

    If it's not very far I'd get a length of suction hose from Lowes, etc. and put one ind in the water and hook the other end to the pump suction. That way you could run the pump and see if the bubbles continue. That'll tell you if it's the underground piping.
    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
    Pool School ----- Pool Math ----- TF-Test Kit

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    Join Date
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    Re: Pump partially losing prime

    Welcome to TFP!!

    Just to add to Bama's advice- prime the temp hose first, or you'll surly have an air issue
    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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    Re: Pump partially losing prime

    Waste - Thanks for the welcome.

    Bama - Your advice worked great.

    I have setup an above ground PVC connection from the pump to the pool and the problem has disappeared. I still have air bubbles coming out of the jets and more then normal air at the top of the leaf basket when the pump is running. However, I used some threaded elbows in my new PVC piping and have not properly sealed them which could be the problem.

    Could the air have to do with anything within the pump? I have read that with some pumps, seals that go bad can cause air in the jets but typically not within the leaf basket.

    My next steps will be to get the pool clear and dig up the ground in front of the pump. When the pool equipment was replaced in 2010. The contractor mentioned the original piping was 1" and he used 1.5" from somewhere below ground to the new equipment. I am hoping the problem is at his work and not below my deck.

    Kevin

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    JasonLion's Avatar
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    Re: Pump partially losing prime

    Yes, if the seal on the pump stainer basket lid is bad you can get air in the jets and often in the pump basket as well.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Pump partially losing prime

    Hey guys, I'm new here but I wanted to add to JasonLion's point. If the gasket attached to the lid of the pump strainer basket has stretched, you won't be able to get a complete seal. Believe it or not, I cut the excess from the gasket, used a little vasoline on the edges and carefully fit the lid back on the basket. The result was a complete seal in place of a steady leak.

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    linen's Avatar
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    Re: Pump partially losing prime

    Quote Originally Posted by Sunsoakin
    used a little vasoline on the edges
    We recommend silicone or Teflon lube not Vaseline or other petroleum based products that can harden and damage the rubber gasket.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Pump partially losing prime

    Thank you linen, I'll be sure to switch!

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