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Thread: Low Filter PSI after Variable Speed Pump Installed

  1. Back To Top    #1

    Join Date
    Feb 2012
    San Diego, CA

    Low Filter PSI after Variable Speed Pump Installed

    Hello All,

    I just replaced my old 1.5 HP Hayward Super pump with a Pentair VS 11018, with the old Hayward the DE filter would show a PSI of around 10 to 15 and now with the Pentair I need to run the pump at 2400 RPM to get that same 10 PSI, which does not save much money. I have read that these VS pumps should be able to run around 1300 RPM and when I set mine to that the filter reports 0 PSI.

    I am not sure if this is normal, the plumbing is PVC 1.5 except for the return which is old copper pipe around 1 to 1.25. The flow appears ok at 1300 RPM but I am not sure if it is filtering properly as I get Algae buildup during hot days. What is the best way to calibrate that I am getting the proper turn over. I have a fairly large very old pool 15ft wide x 35 ft long and 10 ft deep in the deepest to around 4 ft in the shallow.

    Any help would be greatly appreciated.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Low Filter PSI after Variable Speed Pump Installed

    Welcome to TFP!

    That is all very normal. You need to run around 2400 RPM when adding DE to the filter and when using a manual vacuum, but otherwise running around 1300 RPM is just fine. The filter will read a low pressure, and that is just fine.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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