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Thread: Pump Motor Replacement Question for the Experts

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    Pump Motor Replacement Question for the Experts

    I'm looking into replacing the single speed 1hp pump motor I have with a two speed. The pump is a Pentair Whisperflow WFE-4. The motor was replaced prior to us buying the house, but here are the details (and please pardon my book):

    A.O. Century Centurion B2841 Square Flanged Full Rated
    HP: 1
    SF: 1.65
    Frame: 56Y

    The pool is about 14,000 gallons with a roughly 500 gallon attached spa. The pump runs both pool and spa through a Sta-Rite PTM135 cart. filter. The plumbing (as far as I can tell without digging up part of the yard) is 2" from the pool drain/skimmer (drain/skimmer are plumbed together) as well as 2" from the spa drain. There are 2 returns to the pool and 3 to the spa, all at 1-1/2". Again, this is what I see above ground. Equipment is about 12' from the pool.

    Now I beleive I could do a 1:1 swap of the motor and call it a day, but here's a wrench in the works. If I run both the pool and spa suction valves full open and pool and spa return valves full open, the water level in the spa will slowly decrease (I estimate about 1 hour until it would be completely empty, though I've never tested that). Basically it's pulling water out of the spa faster than it can replace it. There does not seem to be a flow problem. All three spa jets have equal pressure. If I run the pump only for the spa, it obviously doesn't drain the spa, but pressure on the filter goes up by about 5-6psi. I have no leaks that I'm aware of (no water loss other than evaporation). What I have to do is either run with the both (pool/spa) return valves fully open and partially close the suction side spa valve to restrict the drain (this is what I usually do) or run with the pool return valve partially closed to restrict flow to the pool (I don't do this as I fear I don't get adequate circulation in the pool).

    whew...

    Okay, onto my questions; If, instead of a 1hp, I buy a 1-1/2hp two-speed motor, do you think it...
    1) would have enough oomph, at either speed, to have both suction and return valves for pool and spa fully open?
    2) would overwhelm and subsequently damage the filter and/or return plumbing?

    Normal pressure on the filter is:

    17psi when both pool and spa are running (spa suction restricted at valve)
    19psi when only to pool
    23psi when only to spa

    Eventually (next year hopefully) I want to move the equipment pad, replace the cart. filter with a DE and buy a 1hp VS pump for the pool and reuse the current one for the spa. With the two speed motor I estimate saving, on average, $40-50/month in electricity costs (location is Camarillo, CA), so the ROI should be less than a year. I'll be doing the work myself, so no additional costs other than the cost the motor, tax and shipping.

    I also wouldn't mind the more powerful pump, if possible, just to get a little better massaging action on the spa jets. The returns in my brother-in-law's spa will almost peel your skin off. I really enjoyed that...

    The replacement motors I have in mind are (not necessarily from this site... still shopping):

    1HP Motor
    1-1/2HP Motor

    Thank you in advance for any help or advice.
    14,000 Gal IG Pool/500 Gal Attached Spa
    Pentair Whisperflow 1hp Single Speed Pump
    Sta-Rite Posi-Flo PTM-135 Cartridge Filter
    Hayward H400 Natural Gas Heater

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    JasonLion's Avatar
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    May 2007
    Location
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    Re: Pump Motor Replacement Question for the Experts

    Getting a larger motor is not enough to make it a more powerful pump, you also need to get a larger impeller. The impeller is what determines how much water the system moves. Impellers don't cost that much, and you have to remove and reinstall the old one anyway when replacing the motor, so not a big deal but important to be aware of.

    The filter pressure is already fairly high. I wouldn't recommend trying the larger pump with the existing filter. It isn't all that likely to self destruct, but it would shorten the cartridge lifetime.

    Running both pool and spa, suction and return, at the same time will never maintain the water level in the spa, no matter what pump you get or what else you change. That can't ever work. For that matter, I don't have any idea why you would want to do that.

    I like the 2Green motors.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Pump Motor Replacement Question for the Experts

    Thanks Jason. Very useful info

    In regard to running pool and spa at the same time... I guess it was just a matter of convenience for filtration and circulation during the day while I'm at work. I don't have any automation other than the Intermatic timer.
    14,000 Gal IG Pool/500 Gal Attached Spa
    Pentair Whisperflow 1hp Single Speed Pump
    Sta-Rite Posi-Flo PTM-135 Cartridge Filter
    Hayward H400 Natural Gas Heater

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    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
    Posts
    37,879

    Re: Pump Motor Replacement Question for the Experts

    I assume the spa has a spillover? If so, I would adjust the valves so that suction is only from the pool, and the spa is set to spillover slowly. That should still leave you with plenty of circulation in the pool and will more than enough to take care of the spa.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. Back To Top    #5

    Re: Pump Motor Replacement Question for the Experts

    Advice greatly appreciated sir...
    14,000 Gal IG Pool/500 Gal Attached Spa
    Pentair Whisperflow 1hp Single Speed Pump
    Sta-Rite Posi-Flo PTM-135 Cartridge Filter
    Hayward H400 Natural Gas Heater

  6. Back To Top    #6

    Re: Pump Motor Replacement Question for the Experts

    Resurrecting a dead thread...

    I'm going to pull the trigger on the 1HP 2Green motor. I'm on the fence regarding the B2982T (integrated digital timer) and B2982 (no timer). Wiring in the B2982 sounds pretty straight forward and I like simplicity, but I also like the idea of a digital timer, so I have a few questions:

    1) Can the timer box be removed from the motor housing? All the images I've found show the timer mounted to the motor, but can it be removed and mounted to a nearby wall? This is minor in the way of complaints, but I don't really want to be bent over every time I want to turn on the pump manually or fiddle with the settings.

    2) Currently my heater is wired into the Intermatic timer and will only turn on when the pump is running. Is there any way to do this with the digital timer? I tried searching (here and Google), but didn't find much.

    3) How robust is the digital timer? Will it last as long as the motor does (hopefully 5+ years)?

    I realize the 2Green motors are still relatively new, so there may be no answers to my questions.

    Anyway, thanks in advance for any input.
    14,000 Gal IG Pool/500 Gal Attached Spa
    Pentair Whisperflow 1hp Single Speed Pump
    Sta-Rite Posi-Flo PTM-135 Cartridge Filter
    Hayward H400 Natural Gas Heater

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    mas985's Avatar
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    May 2007
    Location
    Pleasanton, CA
    Posts
    11,482

    Re: Pump Motor Replacement Question for the Experts

    I realize the 2Green motors are still relatively new, so there may be no answers to my questions.
    Not that new. I know they have been around for at least three years.

    If the timer ever failed, I am pretty sure you can bypass it and use an external timer.
    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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