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Thread: DE back flowing into pool

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    DE back flowing into pool

    Recently I replaced the DE filter grids without any issues. Just observed that the filter is back flowing through the pump when the timer shuts off. I don't have a check valve between the pump and the filter. Could this be a problem with the multiport valve on the Pentair DE filter? The DE doesn't get back to the pool when the pump is running, only when the pump shuts off.

    Any suggestions?
    Fiberglass Trilogy Pool,
    15x34 8900 gal.
    Pentair 1hp Super-Flo Pump
    Pentair CC100 Cartridge Filter, Pentair "Legend" Cleaner

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    Join Date
    May 2013
    Location
    South Jersey
    Posts
    24

    Re: DE back flowing into pool

    Sounds like a bad seal on the multiport valve to me
    25000 Gallon Pentair Intellichlor SWG Gunnite Pool with Heyward DE Filter/Pump
    Test Kit - Taylor K 2006

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    Charlie_R's Avatar
    Join Date
    May 2013
    Location
    Mexico, MO
    Posts
    2,156

    Re: DE back flowing into pool

    Is it coming out the return or coming back through the pump? If pump, make sure you released all the air from your filter.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

  4. Back To Top    #4

    Re: DE back flowing into pool

    Yes it's coming back through the filter. There is no air in the filter. It is siphoning back into the pool through the skimmers and main drain. Never had this happen before.
    Fiberglass Trilogy Pool,
    15x34 8900 gal.
    Pentair 1hp Super-Flo Pump
    Pentair CC100 Cartridge Filter, Pentair "Legend" Cleaner

  5. Back To Top    #5

    Re: DE back flowing into pool

    Is a bad seal in the multiport valve the most logical cause of this issue? There is a lot of cavitation like noise coming from the valve.
    Fiberglass Trilogy Pool,
    15x34 8900 gal.
    Pentair 1hp Super-Flo Pump
    Pentair CC100 Cartridge Filter, Pentair "Legend" Cleaner

  6. Back To Top    #6
    Charlie_R's Avatar
    Join Date
    May 2013
    Location
    Mexico, MO
    Posts
    2,156

    Re: DE back flowing into pool

    Is there air in your pump's strainer basket?
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

  7. Back To Top    #7

    Re: DE back flowing into pool

    No air in the basket, but not too long after the pump stops I can see through the clear cover that the DE flows back into the filter basket.
    Fiberglass Trilogy Pool,
    15x34 8900 gal.
    Pentair 1hp Super-Flo Pump
    Pentair CC100 Cartridge Filter, Pentair "Legend" Cleaner

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