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Thread: Will upgrade of pump help?

  1. Back To Top    #1

    Join Date
    Mar 2016

    Will upgrade of pump help?

    Stats as I know them:


    Pool: 20,400 gal

    Filter: new 60 sq ft Pentair DE
    Max flow rate of filter: 150 GPM

    Pump and filter plumbing: 2" PVC
    Max Flow Rate 2" PVC: 100 GPM (Another said 73 GPM)

    Pump: AO Smith USQ1102 1HP (SF 1.25) with matching 1HP impeller

    feet head (as estimated by inyopools formula):

    Shallow End Skimmer: 10 + 12 = 22 feet
    Deep end Skimmer: 22 + 7 + 28 + 12 = 69 feet
    Deep End Drain: 10 (feet deep) + 22 + 28 + 12 = 72 feet

    Avg: (22+69+72)/3 = 54.3333 feet head estimated


    Short history:

    I purchased a house and inherited pool and equipment. The pump motor was an AO Smith USQ1102 1HP (SF 1.25) motor. The motor died. I took it in to get a replacement, the pool store mentioned that the impeller was a 1.5 rated impeller. I ended up purchasing a 1HP exact replacement and a new matched 1HP impeller. Since this "fix", one of the skimmers does not work well (hardly any water movement through it).

    Current problem:

    When I clean our brand new 60 Sq Ft DE filter, the filter pressure is 9lbs and I get unbelievable water flow out the pool jets. The surface roils! However, within a short time (maybe a month), the pressure in the filter builds up to 14lbs and I get no noticeable flow through the pool. I'm sure water is flowing somewhat, but the skimmers are essentially still and the surface of the pool is calm. At this point, the pool water quickly degenerates.

    Question 1 (This is not a backwash question):

    It would seem to me that I should be able to push more than a 5lbs difference between clean and fully dirty filter.
    If I move from a 1 HP motor to a 1.5HP motor (with matching impeller upgrade), would this allow me to push more through or would it just bump up all the pressures and I have the same 5lbs difference?

    Question 2:

    If an upgrade is a good idea, what is a good pump motor/impeller combination? The whole (feet head + service factor + xxx) leaves me dizzy.

    Question 3:

    If an upgrade is a good idea, is there any benefit to replacing the pump housing/filter basket? I'm not a fan of the spin off lid that I have now... I'd like a lid that is easier to remove and attaches/seals easily.

    Thanks in advance for your thoughts (especially on Q1).

    - Steve

  2. Back To Top    #2

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    cowboycasey's Avatar
    Join Date
    Jul 2013
    Fletcher, OK

    Re: Will upgrade of pump help?

    Steve, you have found the number 1 reason people love and hate DE filters... the good, They work great and filter every little thing out of your water... the bad, they filter every little thing out of your water

    q1. at 9 psi you should be cleaning/backwashing/bumping your DE filter by 12 to 13 psi (25%) as you have seen 14 psi has almost slowed your flow down to a standstill.... this has nothing to do with feet head of your pump, because you state "the filter pressure is 9lbs and I get unbelievable water flow out the pool jets. The surface roils!" so your filter is stopping the flow..

    q2. leaves me dizzy also

    q3. I have a rubber mallet to assist in sealing and spinning on and off the pump basket top.. it works great and is very easy, just light taps and it goes on and off easy
    Steel Grip Mallet 16 Oz Hardwood - -
    Pool: Intex 16x32 15000 gal, 2 speed 340042, Pentair CC320 Filter, CircuPool SJ45 Salt System, Intermatic PE653RC; Hot Tub: 650 Gal SWG Megachlor
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  3. Back To Top    #3
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: Will upgrade of pump help?

    Welcome to TFP!!!

    I am not sure there is an equipment problem here.
    We recommend backwashing when the pressure rises 20-25% over the clean pressure, otherwise the flow drops as you saw. Sounds like you just need to backwash more often.

    Which brings me to my next question, why is your pressure rising so fast?
    Either you have a LOT of dirt added to your pool, or maybe more likely, you have a low level algae bloom that is clogging things up.

    How does your water look?
    How do you chlorinate?
    What are your test results?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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