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Thread: New variable speed pump - what should the de filter pressure be?

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    New variable speed pump - what should the de filter pressure be?

    We replaced our single speed pentair whisperflo 1.5hp pump with a Pentair IntelliFlo 011018 3HP Variable Speed Pump w/ Timer.
    We opened the pool this week and now i realized that when the pump is on different speeds the de filter pressure is crazy different.
    What is a good starting pressure - is it the one when its on max? When do we backwash?
    I think the old one started around 18 and we backwashed around 22.
    NJ
    35,000 gallons, DE filter, IG plaster
    TF-100

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    Mod Squad Jimrahbe's Avatar
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    Re: New variable speed pump - what should the de filter pressure be?

    When the filter is clean, adjust the pump speed so that the pressure is about 15 or so, the specific PSI is not all that important. Record what the RPM is. Use this RPM as your reference point in the future when you are checking the pressure.

    Personally, I never backwash anymore. With the pump running at low speed most of the time, I find it easier to just tear them apart twice a year and clean them. I also do that with the cartridge filter I have at my house.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    mas985's Avatar
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    Re: New variable speed pump - what should the de filter pressure be?

    Filter pressure will be proportional to the RPM^2 so you will get a wide range of pressure values as you change speed.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: New variable speed pump - what should the de filter pressure be?

    hmm ok i was more worried because i know if the filter runs high then something might be wrong with it so since its the beginning of the season and its 10 yrs old i wanted to make sure i wasn't missing a sign of something wrong.
    NJ
    35,000 gallons, DE filter, IG plaster
    TF-100

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    Mod Squad Jimrahbe's Avatar
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    Re: New variable speed pump - what should the de filter pressure be?

    I doubt if anything is wrong with it, but I bet when you first turn the pump on the Pressure gage goes up to 30 or more. At what RPM does the "clean" pressure get to 10? My guess is about 2200 RPM.

    The purpose of a VS pump is so that you can run it slow most of the time. Mine runs at about 1000 PM most of the time and the PSI gauge reads about 3 PSI.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    Richard320's Avatar
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    Re: New variable speed pump - what should the de filter pressure be?

    I'd run it full speed to get the baseline pressure, the way us luddites with single-speed pumps do. And pay attention to which valves are where when you take your readings.
    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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