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Thread: Lack of pressure

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    Lack of pressure

    I have a 22,000 gallon in-ground with 3/4HP Hayward Super Pump and S-244T sand filter. The pool is 13 years old, all original equipment. Live in NC, operate pool 5 months per year.

    Toward end of last summer and much worse when opening this spring I have noticed that the pump is not building up pressure in the filter the way it normally does. Water not flowing into the filter as strong as normal. Pressure gauge (just replaced it) reading really low, almost zero. Unable to run Barracuda cleaner (not enough suction). Not filtering well. Noticed air bubbles coming into pool and a slight leak at base of pvc coming out of pump to filter. I thought that perhaps the pvc was loose or broken, so cut the pipe and replaced with new pipe and coupling, making sure to tighten well at pump exit. But no change, I still get a small amount of water at pump exit, base of the PVC to the filter. And pressure still too low.

    Also, wondering if I need to replace/clean the sand in the filter. Don't think this is related to the problem, but perhaps it is. The filter has never been opened since original installation.

    Thanks for any suggestions.

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    Re: Lack of pressure

    If you have never replaced the sand before I recommend that. You may want to pull the pump apart and check the impellar for obstructions. I repaired one last month that the impellar ring broke and got sucked in the impellar.

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    Re: Lack of pressure

    mb,

    Welcome to the forum!! You have a restriction or blockage on the suction side of your system. That means that somewhere between the skimmer(s) and the impellor, water is not being allowed to flow to the pump.

    The impellor could also have junk in it or be broken so inspect that as well.

    Once you find that restriction and clear it, your flow will return.

    The sand is irrelevant to this problem but once you solve this problem, it's a good idea to open the filter and clean the sand. Take it one step at a time and get your water flowing first.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Lack of pressure

    Quote Originally Posted by duraleigh
    You have a restriction or blockage on the suction side of your system. That means that somewhere between the skimmer(s) and the impellor, water is not being allowed to flow to the pump.

    The impellor could also have junk in it or be broken so inspect that as well.
    Forgive my ignorance: what's an impellor? impeller? (Either spelling, don't know what it is.)

    And what's the best way to find and try to remove the blockage? One skimmer, with an underground line from there to the pump.

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    Mod Squad JohnT's Avatar
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    Re: Lack of pressure

    Quote Originally Posted by mbwalker

    Forgive my ignorance: what's an impellor? impeller? (Either spelling, don't know what it is.)

    And what's the best way to find and try to remove the blockage? One skimmer, with an underground line from there to the pump.
    It's the part of the pump that moves the water. The pump strainer basket has two holes; one is where the skimmer pipe connects, and the other is near the bottom. Turn the pump off and shut off the breaker, and you can pull the strainer basket out and put your finger in the hole to access the impeller. It's a plastic disk, and you are just checking to see if that area is clean. Pine needles, leaves and hair are common problems in there.

    Most likely you have a leak allowing air into the system. Make sure to lube your pump strainer basket lid O-ring with pool lube and make sure the lid is tight. Check the drain plug on the bottom of the strainer basket housing as well. If water squirts or drips out anyplace right as you shut the pump off, that's a probable location of an air leak.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Re: Lack of pressure

    Thanks, I checked out the impeller and it seemed clear, rotated by hand freely, but went ahead and cleaned everything out in the basket and around the seal anyway, and reinstalled the drain plugs in the basket also. Right now the pump is definitely working a bit better (though not as strong as it used to), so I may have a small air leak somewhere else.

    Don't know what pool lube is, I assume that helps the pump basket o-ring seal a bit better. The o-ring seems to be sealing ok, but the rubber's definitely getting worn and stiff. I know that vaseline isn't good for rubber, is there another alternative? Or should I just try to find a new o-ring?

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    Mod Squad JohnT's Avatar
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    Re: Lack of pressure

    Quote Originally Posted by mbwalker
    Don't know what pool lube is, I assume that helps the pump basket o-ring seal a bit better. The o-ring seems to be sealing ok, but the rubber's definitely getting worn and stiff. I know that vaseline isn't good for rubber, is there another alternative? Or should I just try to find a new o-ring?
    Pool Lube is a silicon based grease for O-rings. If your O-ring is showing its age, replace it and lube the replacement. They are too cheap to fool with an old one.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Re: Lack of pressure

    When the pump is running, do you see only water in the pump strainer or do you see air in there, too?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Lack of pressure

    Quote Originally Posted by duraleigh
    When the pump is running, do you see only water in the pump strainer or do you see air in there, too?
    When the pump is running well (not now), the water comes in strong enough to splash against the top of the basket or (at its best) to swirl around at the top of the basket. When it's not running that well (like now), the water doesn't come in as quickly, you can see the stream coming in, and there's air (but not bubbles) between the water coming in and the top of the basket. The pump sounds fine when it's running, no strange noises or high pitched whine.

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    Mod Squad JohnT's Avatar
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    Re: Lack of pressure

    If everything is right, you shouldn't be able to tell if the basket is full or empty. No bubbles. The only motion would be the occasional piece of debris fluttering around.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Re: Lack of pressure

    Quote Originally Posted by JohnT
    If everything is right, you shouldn't be able to tell if the basket is full or empty. No bubbles. The only motion would be the occasional piece of debris fluttering around.
    Well, then everything isn't right. Perhaps a new o-ring will help.

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    Re: Lack of pressure

    Yeah, until you get all that air out of the pump basket, the pump will not function well. AS JohnT said, it should be completely full of water with no visible air of any kind.

    Since you do have air, you have to find where the air is leaking in (somewhere between the skimmer(s) and the pump) and once that is fixed your pump will begin to work effectively.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Lack of pressure

    Well, everything's still not right. Replaced o-ring, used pool lube, cleaned around impeller, even cut and replaced PVC pipe coming in and out of the pump.

    Any other suggestions? Hate to have to call someone, don't really trust the local pool people, but may be at that point.

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    Mod Squad Bama Rambler's Avatar
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    Re: Lack of pressure

    How's your water level in the skimmer?
    Is it sucking air?
    Make sure the weir is working correctly.
    Make sure your skimmer basket is clear.
    You could also be sucking air around the shaft seal. I'd probably replace that if you don't find the problem somewhere else.
    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
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    Re: Lack of pressure

    Quote Originally Posted by Bama Rambler
    How's your water level in the skimmer?
    Is it sucking air?
    Make sure the weir is working correctly.
    Make sure your skimmer basket is clear.
    You could also be sucking air around the shaft seal. I'd probably replace that if you don't find the problem somewhere else.
    Water level's fine in the skimmer. Not sucking air.

    Not sure what a weir is, nor where the shaft seal is.

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    Mod Squad Bama Rambler's Avatar
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    Re: Lack of pressure

    The weir is in the skimmer. It's the thing that swings and lets water run over it.

    The shaft seal is on the pump between the motor and wet end. It's what keeps the water from leaking out while allowing the motor to turn.
    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
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