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Thread: Whisperflo - motor replacement advice

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    Whisperflo - motor replacement advice

    Recently, the motor started making a terrible high pitch sound. Probably bearings. I am thinking of replacing the motor + getting a seal kit, which should be relatively easy and probably cost the same as servicing the existing one.

    The motor that's installed is an AO Smith 3/4 HP and the pool has a 20,000 gallons. My questions:

    (1) Any recommendations as to where I should get the motor?
    (2) Is the existing motor sized correctly?
    (3) Any other thing I should know? I've never done anything like that but I am fairly handy.

    Thanks!
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Mod Squad jblizzle's Avatar
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    Re: Whisperflo - motor replacement advice

    There is always the option of going with a 2 speed motor. Depending on how your current one is wired, you might have to upsize the motor, but you would still save money on energy by running in low speed most of the time and only using high speed when you need it.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
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    Re: Whisperflo - motor replacement advice

    I found the original sticker of the Whisperflo. It says:

    3/4 HP
    Service Factor: 1.27

    The AO Smith motor that's currently installed is 3/4HP / 1.65 SF
    I looked for replacement motors and found 2 AO Smith options: one with SF 1.25 and one with SF 1.65 - which one should I get?
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Mod Squad jblizzle's Avatar
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    Re: Whisperflo - motor replacement advice

    I am confused. The two scale factors are the same?

    You just need a 3/4 with scale factor 1.25 as a minimum to match the original.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    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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    Re: Whisperflo - motor replacement advice

    Sorry. A typo... should have said: "one with SF 1.25 and one with SF 1.65". I edited the original post. Thanks!
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Re: Whisperflo - motor replacement advice

    As long as the HP times the service factor is sufficient for the pump's impeller, you're good to go. The impeller is the limiting factor. In other words any 3/4 HP motor with a service factor greater than 1.27 will do the job. The bigger service factor means that the motor won't work as hard.
    And, unless you have water features, 3/4 HP is fine for 20,000 gallons.

    EDITED to fix service factor typo (sorry)
    In the industry, CSP (Certified Service Professional) by the NSPI and it's successor the APSP. My company services over 600 pools every year. I think the practices regularly espoused on this forum (especially the BBB method) are outstanding; however my comments will be often oriented towards the goal of getting it done, and getting it done right now!

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    mas985's Avatar
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    Re: Whisperflo - motor replacement advice

    Quote Originally Posted by Qwaxalot
    In other words any 3/4 HP motor with a service factor greater than 1 will do the job.
    I think you meant anything greater than 1.27 since that was the original service factor.
    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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    Re: Whisperflo - motor replacement advice

    For the OP - what you need to look for in a motor is anything with a SFHP (SF x HP) rating of .9525 or greater. 1 HP motor with a SF of 1.0 would meet this as well. I can't comment on how its energy use would compare to the 3/4 HP with the 1.27 SF however, it would run the pump without overloading the motor..
    16x32 IG 19,000 gallons, Pentair 1.5 hp Energy Efficient Superflo pump (348024),vinyl liner, Chlorine dispenser, Hayward S-244T sand filter

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    Re: Whisperflo - motor replacement advice

    Thanks!!!
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Re: Whisperflo - motor replacement advice

    Quote Originally Posted by mas985
    Quote Originally Posted by Qwaxalot
    In other words any 3/4 HP motor with a service factor greater than 1 will do the job.
    I think you meant anything greater than 1.27 since that was the original service factor.
    You're right, I fixed it.
    In the industry, CSP (Certified Service Professional) by the NSPI and it's successor the APSP. My company services over 600 pools every year. I think the practices regularly espoused on this forum (especially the BBB method) are outstanding; however my comments will be often oriented towards the goal of getting it done, and getting it done right now!

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    Re: Whisperflo - motor replacement advice

    I ordered a new motor, Energy Efficient SF 1.65 and 3/4 HP.
    This might be a silly question: when I remove the old motor from the pump, do I need to do anything with the valves/diverters to avoid getting soaked or would the valve in "filter" position prevent the water from coming back from the tank?
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Mod Squad Bama Rambler's Avatar
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    Re: Whisperflo - motor replacement advice

    If the pump is above the waterline you really don't have to do anything. If it's below the waterline you'll have to shut off the suction and return line. Since you've given us very minimal info about your setup we can't be of more help.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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    Re: Whisperflo - motor replacement advice

    I have been a pool owner for 2 years, so pretty much everything is new to me and I do not even know what information is needed
    The filter and pump are above water line. I was mainly concerned about the water from the filter tank coming back...
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Mod Squad jblizzle's Avatar
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    Re: Whisperflo - motor replacement advice

    What kind of filter is it? (add your pool and equipment info to your signature)
    Do you have a multi-valve on the filter that you can close?

    If not, some of the water will drain out of the filter ... not really a big deal. Or just open the drain valve on the filter.
    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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    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Mod Squad Bama Rambler's Avatar
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    Re: Whisperflo - motor replacement advice

    You could always drain the filter if it's a concern.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Whisperflo - motor replacement advice

    Signature updated! I just noticed that my valve has a "closed" position. That should probably help.
    Now, all that's left is to hope that my existing motor will live just a couple of days more, until its replacement arrives. It is making a terrible noise!

    Thanks for all the help! Much appreciated!
    Guy
    ~20k gallon IG plaster pool, Pentair 3/4HP Whisperflo, Pentair FNS Plus 48 DE filter, IntelliClor IC40 Salt Generator, Pentair Legend Platinum Robotic Cleaner

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    Mod Squad Bama Rambler's Avatar
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    Re: Whisperflo - motor replacement advice

    Putting the multiport in closed will keep the filter from draining out when you open the pump.

    Since you have a DE filter, when was the last time you opened it and cleaned the grids well? If it's been a while I'd suggest taking this time to go ahead and do that while you have the system down anyway.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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