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Thread: Just changed cartridge filters and PSI went up , not down???

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    rugadog's Avatar
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    Just changed cartridge filters and PSI went up , not down???

    Hey all,
    I just replaced my old 4 cartridge filters (Pentair -model# 17-8580) with new Unicel # C-7470. I nozzle spray cleaned the old ones about a month ago then re-installed them a began turning turning my pool from green back to sparkling clear. So the old, spray cleaned filters ran for a month after the pool was clean. I just replaced the old ones with the new Unicel filters. Just before I opened the filter housing the running PSI was 18". The PSI is 20" after I installed the new filters. Is this normal?

    Thanks in advance!
    NEW POOL: Completed, 11/23/11
    44,000 gallons
    Filter: Pentair -model# CCP520, Cartridge, 150 GPM (17-8585)
    In ground ~ Pebble Sheen
    Pentair IntelliChlor IC40 ~ SWG
    Main and Small waterfall pump: IntelliFlo ~ 3HP,
    Big Waterfall pump: WhisperFlo ~ 1-1/2HP
    Polaris 280 F5 with Century Centurion 3/4HP booster pump

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    Re: Just changed cartridge filters and PSI went up , not down???

    Are both filters rated for the same GPM? Is there a micron rating on each to compare? Both of these could account for an increase in pressure. Also are you sure nothing fell in the housing that could have blocked the flow a bit?
    coloeb,
    20k gal. IG fiberglass/plaster rectangle 32'x16'
    Hayward Superpump 3/4 H.P. primary Hayward model 5060 Booster Pump
    Hayward Pro Series High Rate Sand Filter
    Pentair Model 320 automatic Chlorine/bromine in-line feeder

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    rugadog's Avatar
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    May 2009
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    Re: Just changed cartridge filters and PSI went up , not down???

    Actually, I gave you the wrong info. for the filter I bought, it's actually Pleatco # PCC80. All three filters(Pleatco # PCC80, Pentair 17-8580, Unicel # C-7470) are supposed to be directly interchangeable, though. According to every distributor website I visit. I checked and there's nothing I dropped inside blocking flow. Thanks for the suggestions.

    Does anyone have have any idea why my pressure would go up? Is this common with brand new filters?
    NEW POOL: Completed, 11/23/11
    44,000 gallons
    Filter: Pentair -model# CCP520, Cartridge, 150 GPM (17-8585)
    In ground ~ Pebble Sheen
    Pentair IntelliChlor IC40 ~ SWG
    Main and Small waterfall pump: IntelliFlo ~ 3HP,
    Big Waterfall pump: WhisperFlo ~ 1-1/2HP
    Polaris 280 F5 with Century Centurion 3/4HP booster pump

  4. Back To Top    #4

    Re: Just changed cartridge filters and PSI went up , not down???

    Do you have a guage on the supply side and discharge side of the filter? Sometimes units are set up like this to measure the pressure drop across the filter itself. It could be that the new filter has a bit more resistance to flow than the old.Was the old filter damaged in such a way that water could pass easier, like a hole?
    coloeb,
    20k gal. IG fiberglass/plaster rectangle 32'x16'
    Hayward Superpump 3/4 H.P. primary Hayward model 5060 Booster Pump
    Hayward Pro Series High Rate Sand Filter
    Pentair Model 320 automatic Chlorine/bromine in-line feeder

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    rugadog's Avatar
    Join Date
    May 2009
    Location
    USA
    Posts
    19

    Re: Just changed cartridge filters and PSI went up , not down???

    No, I just have the one gauge on top of the filter housing.

    The old filters didn't have any obvious holes, but I didn't get a chance to thoroughly look at them. Because they were so old I put them in the trash yesterday morning and the garbageman came shortly thereafter. My filter housing nameplate shows it can handle 50", so the 20"-28" isn't going to do anything except work the pump motor harder (I guess?)
    NEW POOL: Completed, 11/23/11
    44,000 gallons
    Filter: Pentair -model# CCP520, Cartridge, 150 GPM (17-8585)
    In ground ~ Pebble Sheen
    Pentair IntelliChlor IC40 ~ SWG
    Main and Small waterfall pump: IntelliFlo ~ 3HP,
    Big Waterfall pump: WhisperFlo ~ 1-1/2HP
    Polaris 280 F5 with Century Centurion 3/4HP booster pump

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