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Thread: Pump loosing prime

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    Pump loosing prime

    My pump keeps loosing prime. I believe it may be the discharge connection as shown in the picture because I removed the top this morning and primed the pump. As it was running there was I water leak there and when I wiggled it a little bit back and forth it sounded like it was sucking air.

    So am I on the right track with my diagnoses? If so is there a special type of PVC for these or can I just go to HomeDepot and get the 2" PVC I need?

    As always thanks for the help,

    JB
    Attached Images Attached Images
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump loosing prime

    While you should probably fix that leak, it's not the resaon your losing prime. leaks on the discharge of the pump can't suck in air when the pump is running.

    If you're losing prime while the pump is running, it's a suction side leak somewhere. Common places are the lid and the drain plugs. After that is the inlet fitting and then valves and fittings between the pump and skimmer. Also low water level in the skimmer and/ or a sticking weir will cause it.
    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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    Mod Squad jblizzle's Avatar
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    Re: Pump loosing prime

    Although if you only lose prime when the pump is off, the discharge leak could be where the air is allowed back into the system and letting the pump drain.

    Do you see any air in the basket when the pump is running? Any problem with the pump priming when turned on?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Pump loosing prime

    Quote Originally Posted by Bama Rambler
    While you should probably fix that leak, it's not the resaon your losing prime. leaks on the discharge of the pump can't suck in air when the pump is running.

    If you're losing prime while the pump is running, it's a suction side leak somewhere. Common places are the lid and the drain plugs. After that is the inlet fitting and then valves and fittings between the pump and skimmer. Also low water level in the skimmer and/ or a sticking weir will cause it.
    Ok I will check the lid, and the drain plug and all the fittings I can. I have good water level in the skimmer but I have no idea what a weir is?

    Thanks
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    linen's Avatar
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    Re: Pump loosing prime

    As for the pipe, I would suggest adding a union to that connection since you are going to have to cut it anyways to fix that seal if it is leaking water when pumping or leaking air when not pumping.
    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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    Mod Squad Bama Rambler's Avatar
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    Re: Pump loosing prime

    The weir is the door inside the skimmer mouth that floats just under the surface of the water when the skimmer is operating.

    Is there a vortex in the skimmer when the pump is running?
    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 loosing prime

    Ok I went out checked everything and now I pretty sure I found the problem. The connection shown in the picture on the intake side is what's sucking air.
    Attached Images Attached Images
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Re: Pump loosing prime

    Is the black pipe CPVC?
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Re: Pump loosing prime

    The dark pipe is more likely schedule 80 PVC. The leak may very well be where those two couplers butt up against one another.

    Again, since it all has to come out, I would suggest putting a union there as well to facilitate pump removal if ever necessary.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    linen's Avatar
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    Re: Pump loosing prime

    I agree with duraleigh, replace with a union and replace the two couplers at the same time with one (unless the one closest to us is a 90, then take a wider picture so we can see what your up against). Whoever installed those pumps were not doing you (or the original owner) a lot of favors (tight spacing and no unions). My guess is this has been a problem before, hence the multiple couplers (they should have at least put a union on the first time they had the problem).
    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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    Ok that didn't work??

    Well I could only make it to Home Depot yesterday and they only had schedule 40 PVC no schedule 80 so I got regular PVC and though I would just give it a temporary fix until I could find the proper pipe. Well as you can see I found out about 3:00am this morning that wasn't going to work the discharge just pushed out? I'm glad the dog was barking at it and I went to check or this would have been very bad
    Attached Images Attached Images
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Re: Pump loosing prime

    Schedule 80 is not at all necessary for pool plumbing. Sched 40 works fine.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pump loosing prime

    Quote Originally Posted by duraleigh
    Schedule 80 is not at all necessary for pool plumbing. Sched 40 works fine.
    Ok thanks, do you think this came apart because I used regular PVC or Siri just not have it in tight enough?
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump loosing prime

    How far did you have it threaded into the discharge port? It should have been almost bottomed out.
    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 loosing prime

    Quote Originally Posted by Bama Rambler
    How far did you have it threaded into the discharge port? It should have been almost bottomed out.

    I thought I had screwed it in there pretty tight but it wasn't bottomed out... I guess maybe I didn't screw it in far enough?
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump loosing prime

    I can't tell from the pictures, but make sure to check the threads in discharge port to make sure they're sharp and deep enough and haven't been cross-threaded. Also when you go to repair it, dry thread the adapter into it to see how far it threads into it and how smoothly.
    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 loosing prime

    Ok will do.

    Thanks Bama
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Re: Pump loosing prime

    I'm guessing some (maybe a lot) on this but that connection on top of your pump into the sched 80 pipe looks to me like it has been taken off/loosened and not sealed back with adequate thread dope.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Well it's one thing after another!

    finally went got all the right connections I needed re-did the intake and discharge connections with schedule 80. Let the glue cure for about 8 hours then I was ready to test it out. Primed the pump made sure everything was good and tight then flipped the switch to turn the pump on.... Well it started sparking and smoking and I immediately turned it of of course... So I guess now my pump motor is burned out it's not seized because the shaft still turns easily but I don't know if it got water in it or what but definitely something wrong???

    I switched the motor for the spa jets for now just so I can get some water circulating until I get this motor rebuilt or replaced....

    Anyone know what would cause the motor to fry like that??
    My pool:
    Built 2004, 14K gal, IG plaster,Pentair WhisperFlo 2 HP pump(1 speed), Pentair FNS Plus DE filter,
    In Floor cleaning system, Attached Spa with Spillover seperate WhisperFlo pump for jets.

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump loosing prime

    I bet it got water in it?

    Did you move the pump while you were repairing the plumbing?
    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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