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Thread: Sizing Replacement Pump or Motor - mas985

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    Join Date
    Sep 2014
    Location
    Tampa Bay, FL
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    Sizing Replacement Pump or Motor - mas985

    Hello, I have a painted concrete, ~7,000 gallon in-ground pool, in Tampa Bay, FL with a non-functioning waterfall (was leaking, so capped line at pump), and I am looking for advice on sizing a new pump or motor. In the future, I would maybe like to get the waterfall functioning again – it is a flagstone, stepped waterfall that has 3-4 outlets at the top where the water flows out of – they don’t look very large in diameter. The water runs down the flagstone steps until it is deposited into the pool.

    Current Equipment:
    • Pentair Whisperflo with 220V A.O. Smith B854 1.5 HP, 56Y Frame Uprate Motor – Motor & Seal plate Replaced in July 2010
    • Pentair Clean & Clear Pool Filter – At least 150 square feet if not 200 square feet based on filter height (sticker on back of filter, not visible due to proximity to wall).
    • I replaced the skimmer early this year due to cracked plastic causing large leak with a Hayward SP10712S Skim-Master Series from Amazon.
    • Tropical 102,000 BTU Pool Heater (hardly ever used, I actually have had the breaker switched off for at least 2 years)
    • ~7,000 gallon pool with 1 main drain, 1 skimmer, 4 return jets
    • Height of pump is about level with the main drain, 36” to return jets height, and 42” to skimmer plumbing height.
    • Pump inlet is 2”, filter plumbing 2”, return jet 1-1/2” plumbing, waterfall return 2-1/2” at pump valve (capped off, not sure of sizing at actual waterfall)
    o Pool Heater & Filter are from previous home with a large 20,000+ gallon pool

    It all started a week ago because I wanted to replace some loud motor bearings. While disassembling the motor, I realized one of the threaded inserts in the seal plate had come loose (the same thing happened in 2010) and I also snapped one of the long quarter-inch retaining bolts

    Now I have 3 options:
    1. Replace with new pump + motor combo, appropriately sized this time.
    2. Replace seal plate, pump gaskets + new 2 speed motor
    3. Replace seal plate, pump gaskets + new 1 speed motor

    I was really interested in the Variable Speed motors until I read some posts by mas985 and downloaded his Excel calculator (I got lost in all the numbers though). I realized in Florida, living 40 miles from Tampa, FL, which is the lightning capital of the world, and also with our low energy rates - $0.11/kwH, it didn’t make sense to get a variable speed. So now I am really torn between the 3 options listed above.

    With option 2, I’d want to also change all the pump gaskets (~$20) and the seal plate ($54) when I factor in a new 2 speed motor (Hayward SPX3210Z2BER 1-Horsepower 2 Speed Energy Efficient Full Rate Motor Replacement for Hayward Tristar SP3200EE Series Pump - $280.99 Amazon.com), it is only $90 more for a Pentair 340042 SuperFlo High Performance Energy Efficient Two Speed Pump, 1 Horsepower, 230 Volt, 1 Phase - $447 off Amazon.

    With option 3, it is a little less expensive, but I don’t know if I’d end up paying more than the difference with option 2 in increased energy usage.

    I look forward to hearing your opinions,

    Frank

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    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
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    Re: Sizing Replacement Pump or Motor - mas985

    Given the problems with your current pump, I would just go with the Superflo. Don't even consider a 1 speed.

    But your waterfall is going to look less exciting so if that is a consideration, then a two speed of similar sized pump as you have now would be appropriate.
    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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    Join Date
    Sep 2014
    Location
    Tampa Bay, FL
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    Re: Sizing Replacement Pump or Motor - mas985

    Thanks for the quick reply!

    So you would recommend the Pentair 1 HP Superflo? I see you have a larger pool and manage to use a 1/2 HP only, is that because you've increase the run time?

    If the waterfall stays capped off, how many hours would you say I need to run for 1 complete turn-over daily on low speed? The 1 speed I was running on the Intermatic Timer for about 4 hours a day during the summer with no issues. Will I have any issues I ever have to run the heater due to low flow?

    And I think I'll have to install a hi-low switch like bobodaclown did on his pump [URL="http://www.troublefreepool.com/threads/59063-Purchased-a-SQL1072-3-4-HP-2-Speed-115V?"] or does the new pump come with the switch?

    Thanks again for your help!

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    mas985's Avatar
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    May 2007
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    Pleasanton, CA
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    Re: Sizing Replacement Pump or Motor - mas985

    No I didn't increase run time and run time really has nothing to do with turnovers. I run my pool 1 hour on high speed and 3 hours on low speed.

    For further reading on run time, read the article in my signature and pool school: http://www.troublefreepool.com/conte...-pump-run-time


    As for the heater, yes, low flow rates can affect the heater but sometimes you can adjust the pressure switch to get it working. It really depends on the heater. But also keep in mind that the heater loses efficiency with lower flow rates (greater heat loss) so you might be better off running at high speed while using the heater.
    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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