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Thread: Pump draws too much water from skimmer

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    Pump draws too much water from skimmer

    I've recently been having this problem with the pool pump. We replaced the pump and filter and added a salt water chlorinator about five years ago. And replaced the inlet plumbing and skimmer last year. The pump ran fine last year and this year up until now.

    What's happening is the pump draws too much water and no matter how full the pool is, It will over pull from the skimmer and the water level collapses and it draws mostly air. The skimmer is the only entry point to the pump. When I hook up the vacuum hose the pump primes just fine and runs at 10psi through the filter. It also over draws when discharging/flushing out the filter.

    My thought was that there isn't enough back pressure through the filter and I flushed and added fresh D.E. powder but that didn't help. I even over added thinking maybe I didn't have enough. And my next move was to open up the filter and inspect it and then refill it with powder, but the fact that it's running at 10psi through the vacuum hose makes me think that won't help.

    Could it be that the pump is set at a (too) high flow rate? Is there a way to regulate that? And how would that change on it's own?

    If anyone has experienced this, I'd appreciate hearing what you did to resolve it or if someone has in-depth knowledge and can explain what's happening and how to fix it, I'd appreciate as well.
    20k 16x32 IG vinyl sided
    Hayward D.E. filter EC65A
    Hayward Superpump 1hp
    No heater method employed
    Brookfield, WI

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    Richard320's Avatar
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    Re: Pump draws too much water from skimmer

    I'd suspect the weir is sticking.

    Water will seek its own level and more than enough should go through the large opening to match the flow through a small pipe opening.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
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    Re: Pump draws too much water from skimmer

    Quote Originally Posted by Richard320 View Post
    I'd suspect the weir is sticking.

    Water will seek its own level and more than enough should go through the large opening to match the flow through a small pipe opening.
    I don't have a weir. I wondered about that, in how can that increase water flow? I read that they're supposed to do that.
    20k 16x32 IG vinyl sided
    Hayward D.E. filter EC65A
    Hayward Superpump 1hp
    No heater method employed
    Brookfield, WI

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    Richard320's Avatar
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    Re: Pump draws too much water from skimmer

    Quote Originally Posted by seecurt View Post
    I don't have a weir. I wondered about that, in how can that increase water flow? I read that they're supposed to do that.
    They actually increase velocity, not flow, by reducing the cross-sectional area. Like how a creek speeds up through a shallow area. If you have no weir, there's no reason the pump is starving for water. Unless the water level is too low, which you say it isn't.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Pump draws too much water from skimmer

    Not sure this would matter, but I shot a video of it to show.

    http://www.youtube.com/watch?v=H4_kx2qSWFM

    I cleaned the filter and added fresh D.E. No difference.

    Anyone think this is cavitation where the water is accelerating through too fast? It is a recent problem and my cleaning and inspection of the filter shows no flaws or damage (where water was simply running through with no resistance). I'm not all that interesting in buying a new pump just to try it...
    20k 16x32 IG vinyl sided
    Hayward D.E. filter EC65A
    Hayward Superpump 1hp
    No heater method employed
    Brookfield, WI

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    Re: Pump draws too much water from skimmer

    Are you absolutely sure there is nothing stuck in the skimmer mouth?....It looks like the restriction is in the skimmer. Hard to see in there, can your get your hand in and feel around?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Pump draws too much water from skimmer

    Quote Originally Posted by duraleigh View Post
    Are you absolutely sure there is nothing stuck in the skimmer mouth?....It looks like the restriction is in the skimmer. Hard to see in there, can your get your hand in and feel around?
    That's an interesting thought. I looked and found nothing. Put a snake in about 18". It's the only snake I have handy right now. I even checked the valve by the pump and found nothing. I'll get a bigger snake tomorrow.

    Would this matter? The skimmer has an 1.5" opening and I'm running 2" pipe to the pump where there is also a 1.5" opening. I was drawing air in the past and replaced all plumbing not covered in concrete before busting it out and ultimately replacing the skimmer with the exact same unit as it had. I was reading about head loss and realized that on my way to the pump there were too many curves and went with the most efficient set up I could use. I did not mess with the return side so it goes from 2" to 1.5" after the chlorinator to the pool.

    The pump might be 2", come to think of it.
    20k 16x32 IG vinyl sided
    Hayward D.E. filter EC65A
    Hayward Superpump 1hp
    No heater method employed
    Brookfield, WI

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    Re: Pump draws too much water from skimmer

    If you don't find anything up inside the skimmer mouth (Not sure why you need a "snake") you can always restrict the flow on the pressure side. Simply putting in smaller eyeball fittings might do it. If you don't mind the work, put a Jandy valve inline just to restrict the flow as needed until it keeps skimmer full.
    I even checked the valve by the pump and found nothing
    Partially close that valve to slow the flow.....that'll do it.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Pump draws too much water from skimmer

    I agree that it appears to be a restriction in the skimmer throat. However, a missing weir makes mine act the same way. It will suck a vortex in the skimmer and allow air to enter the skimmer body and into the pump.
    Dave J. TFP Moderator
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    Re: Pump draws too much water from skimmer

    I remember once where a tennis ball would temporarily get into the vortex and prevented the air from going in.
    don't know if that will help.....
    18X36 Grecian 24400 est., pacfab sand Triton II, 1.5hp AOSmith, clormatic 2

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    Re: Pump draws too much water from skimmer

    My in ground skimmer has a valve affair in the bottom with an adjustable opening sort of like this:

    Hayward SP1082FV Float Valve Assembly

    It sits below the basket.
    SWG: CircuPool (May 2014) SI30+Plus; 3000ppm seems ideal;
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    Re: Pump draws too much water from skimmer

    Thinking about this again, there virtually HAS to be something in the skimmer throat. Water is leaving the skimmer faster than it can come in from the pool. A restriction in the throat is the only thing that makes sense.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pump draws too much water from skimmer

    Agreed, there MUST be something in the skimmer throat. In the video, there is clearly a huge discrepancy between the height of water in the pool and the height of make-up water running into the basket. Unless somebody has repealed the law of gravity, that just can't be.....

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    Re: Pump draws too much water from skimmer

    I think what duraleigh was suggesting is the rectangular opening between the pool and your basket you show in your video. What is happening exactly in your vid? It starts out swirling and looks normal, so I am assuming that the pump is on at least at a slow speed, is that correct? and then when you put on high, it drains the basket. Am i understanding correctly?

    Duraleigh was suggesting that the rectangular opening must be blocked or restricted somehow because while the water level in the pool remains the same (as seen on the waterline on the front of the rectangle, it obviously drops in the basket. Water doesn't work that way, it should level out. Are you sure there isn't an old weir door that got stuck halfway open/closed? What is the measurement of that rectangular opening on the inside closest to the skimmer basket?
    40,000 Gallons- "Lazy L"; IG-Fiberglass; Pentair Clean and Clear+ 520; Circupool VJ3 VS Pump (2.4 SFHP); Circupool SJ-45 SWG

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    Re: Pump draws too much water from skimmer

    I want to thank you guys for your persistence and knowledge. I feel like an idiot because I replaced (busted out the concrete) the skimmer last year with a new one and I swore it did not have a weir. The old one certainly didn't.

    But that's what it was. The weir was stuck.

    I was thinking that the throat was under ground. That's where the snake would come in, to answer that.

    But I'm very happy. The pool is running smoothly. Thanks again for all the help...
    20k 16x32 IG vinyl sided
    Hayward D.E. filter EC65A
    Hayward Superpump 1hp
    No heater method employed
    Brookfield, WI

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    Mod Squad kimkats's Avatar
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    Re: Pump draws too much water from skimmer

    Good job! We can all use this as a learning experience! So glad you found the problem and it was an easy fix!

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    Re: Pump draws too much water from skimmer

    Quote Originally Posted by seecurt View Post
    I want to thank you guys for your persistence and knowledge. I feel like an idiot because I replaced (busted out the concrete) the skimmer last year with a new one and I swore it did not have a weir. The old one certainly didn't.

    But that's what it was. The weir was stuck.

    I was thinking that the throat was under ground. That's where the snake would come in, to answer that.

    But I'm very happy. The pool is running smoothly. Thanks again for all the help...


    Thanks for taking time to make your final post to let us know what was happening. We don't always see OPs closing loops on some of these things.
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