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Thread: Cleaned filter and now pressure is low. What did I do wrong?

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    Cleaned filter and now pressure is low. What did I do wrong?

    We recently bought a house with a pool (I think pool is about 4 years old). This is my first pool so forgive my ignorance and lack of the proper technical terms. I recently opened the Hayward cartridge filter container and cleaned out the filter using a hose. I put it back together just as it came apart, tightened the rings, etc, but now the pressure won't go back up to where it was (around 20-25 psi) and the pump never becomes fully pressurized in the visible area where the pump basket is. However, when the I run the spa filter, it seems to pressurize just fine. I've opened the air release value and while water squirts out it makes no appreciable difference in the pressure. Do I have air in the line or maybe debris or did I fail to do something when putting the cartridge back together??

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    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: Cleaned filter and now pressure is low. What did I do wr

    A cleand filter SHOULD show lower pressure on your gauge cause it is getting better water flow now. Dirty filters produce higher pressures or "resistance".
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
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    linen's Avatar
    Join Date
    Jul 2010
    Twin Cities, MN

    Re: Cleaned filter and now pressure is low. What did I do wr

    Welcome to tfp, seifert1427

    How is the flow at the pool return? What does your pressure gauge read when the pump is off? What pump and filter do you have? Is there air in your pump's leaf basket when the pump is running?

    Ideally sized cartridge filters tend to run much lower than 25 psi. It could be that your filter needed cleaning a long time ago, and now that it is clean it is running at a much lower pressure. We recommend cleaning when the pressure goes up 25% from the clean pressure.
    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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    Join Date
    Jan 2011
    Richmond, Texas

    Re: Cleaned filter and now pressure is low. What did I do wr

    My clean filter runs about 20 PSI and dirty runs close to 30. What is yours running now? Also when I run in spa mode my runs higher.
    Approx 11K Gal. 10'X30' Semi free-form IG - 6 ' raised spa w/6 jets - 10' circle sun shelf with 1 bubbler - Waterfall - 3 / 1.5 HP pumps - Polaris 280 Cleaner - 3 Pentair Color LED Intellibrite Lights - Pentair 400K Master Temp - 2 Valve Actuators - 5 Fiberstar Mini Laminars - 1 Fiberstars 2004 Illuminator - 2 Skimmers - 6 Returns - Caribbean Blue Pebble Tech - 600+ sq ft kool decK - Auto Fill - 2 Boston Acoustics VOYA RK5 Outdoor Rock Speakers - 2 TIC Corporation TFS5CN 6.5-Inch 150-Watt Terra-Forms Rock Speakers - Apple Airport Express - 1 Awesome View.

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    Re: Cleaned filter and now pressure is low. What did I do wr

    My filter was running around 25-30 but now it won't register above 3-4. Clearly there is something wrong. The system doesn't seem to be coming up to full strength. In the pump basket area, before the water would eventually fill the entire space creating a vacuum. Now, water is continually flowing through that space and never fully pressurizing. So it appears that there is air in the pump leaf basket area but again, only when the pool pump runs. With the spa pump, there is no issue.

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Cleaned filter and now pressure is low. What did I do wr

    Very low pressure indicates you either have something blocking the system BETWEEN THE PUMP AND THE SKIMMER or you have an air leak in that same area.

    A clogged impeller is another possibility but not quite as likely. Remove the pump basket lid and put your hand into the impeller to see if you can feel any debris stuck in there

    Check the pump basket's the most common place for air leaks.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana

    Re: Cleaned filter and now pressure is low. What did I do wr

    My guess would be that water is bypassing your filter cartridge. Double check that it is fully seated and has no tears in it.
    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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