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Thread: Filter pressures

  1. Back To Top    #1
    tcat's Avatar
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    May 2012
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    Austin, TX
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    Filter pressures

    Strange phenomenon. I had a 2# check valve in my 2" line after filter, "to" the pool. I just removed it because I thought it was interfering with flow on low motor speed. Pump is 12" above water level so I saw no need for it.

    Filter pressure on low with check valve: 8 psi
    Filter pressure on low without check valve: 12 psi

    I would have though it would drop to 4-6. Does this make sense? Possibly more water is moving without the check valve, so filter is seeing more pressure? It is a pressure valve on top of the filter (not a vacuum valve), right?
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

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    mas985's Avatar
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    Re: Filter pressures

    Usually, reducing head loss after the filter gauge will reduce pressure and not increase pressure. Even with the increased flow, the return head loss (pressure) is still lower than it was before. So either something else changed or your gauge is not working properly.
    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

  3. Back To Top    #3
    tcat's Avatar
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    Re: Filter pressures

    Yeah, odd. Before and after was only about 20 minutes, so must be my gauge. Will look into replacing it. Does go to zero when off, 29 on high, 12 on low.
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

  4. Back To Top    #4
    mas985's Avatar
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    May 2007
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    Pleasanton, CA
    Posts
    11,478

    Re: Filter pressures

    You might also check the plumbing downstream since you modified the plumbing perhaps something got stuck somewhere.
    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

  5. Back To Top    #5
    tcat's Avatar
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    May 2012
    Location
    Austin, TX
    Posts
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    Re: Filter pressures

    Should be no issues there. Just 2 saw cuts with pump off. Water from 4 jets on high or low (pretty slow on low). Not much skimmer action even with drain line shut (but is sucking). Plan on cleaning filter this weekend, but shouldn't be to dirty.

    edit: My low pressure is back down to 8. I added a Poolskim which opened up one of the returns much more than it was, so pressure side restriction went down. Filter pressure seems very sensitive to return opening. All seems to be running fine, so not going to worry about it. If pressure goes up to 10 I'll clean the filter.
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

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