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Thread: Erratic suction pressure while vacuuming

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    Erratic suction pressure while vacuuming

    Hi All,

    This is a recurring problem. When I vacuum the pool, using a very basic set-up (flexi-hose and vacuum head attached to the pool pole), my pump will vacuum for a bit, then lose pressure, then build it back up, then lose it, etc. I get about 10-15 seconds of good vacuuming, then will lose pressure for 4 or 5 seconds. Then I'll get it back, etc. When it loses pressure, that's accompanied bubbling at the return. Sometimes the fluctuations are enough to detach the hose from the vacuum port at the bottom of the skimmer box. The hose is held there merely by suction (it's not a friction fit, but rather loose).

    I always take care to hook the hose up properly (filling it with water and keeping it underwater as I attach it, etc.).

    Any ideas on this?

    best wishes,
    David
    11,500 gal. rectangular cement, 11 x 28 (built c1930); Hayward S180T sand filter; Hayward Max-Flo II 3/4 HP pump

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    Mod Squad YippeeSkippy's Avatar
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    Re: Erratic suction pressure while vacuuming

    Are you turning valves to direct more pressure on the skimmer and less on the drains? That's how I increase my vacuum suction. But making sure you don't close off anything entirely so as to not starve the pump of water.... if that's possible? I dunno?
    Perhaps your valves are turned wrong?
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    Re: Erratic suction pressure while vacuuming

    You are sucking air. Either a hose leak or perhaps the water level is too low in the skimmer but find where the air is getting in and you can vacuum normally.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Erratic suction pressure while vacuuming

    Quote Originally Posted by duraleigh
    You are sucking air. Either a hose leak or perhaps the water level is too low in the skimmer but find where the air is getting in and you can vacuum normally.
    That's the problem: I swear, the entire hose is filled with water before I hook it to the vacuum port, and it remains under water the entire time. Any leak in the hose would be a leak underwater. The water in the skimmer is at least 7 or 8 inches above the vacuum port. Arg.
    11,500 gal. rectangular cement, 11 x 28 (built c1930); Hayward S180T sand filter; Hayward Max-Flo II 3/4 HP pump

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    Re: Erratic suction pressure while vacuuming

    Nevertheless, you are sucking air and that ONLY comes from the suction side of your system. Somewhere on that suction side is a leak and when you find it, your issue will be solved. They are often hard to find but there really is no other common explanation.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    East_Akl_Neil's Avatar
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    Re: Erratic suction pressure while vacuuming

    Sounds like we have simmilar problems. No issues with system untill I start vacumming. To confirm air leak put vacuum hose in as normal, the go watch pump basket, will likly fill with air over a few minutes. Remove vacuum hose and air goes away. Air leak only occurs with increased suction load.
    Next thing to do is find air leak. I know where mine is, just need to fix it before it gets too bad. I can here it next to skimmer, but need to dig it up to repair, or just replace the 35yo plumbing, but that is another thread I need to start.
    Late 1970's 39000L IG Concrete Pool with Vinyl Liner
    Austral FT55 Sand filter
    Hurlcon E170 Pump Brochure,Manual
    32-40mm Pipe work
    Living in beautiful New Zealand

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