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Thread: Changing 1-speed pump motor to 2-speed; slightly complicated

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    Changing 1-speed pump motor to 2-speed; slightly complicated

    Hi all, Just want to say thank you to this forum. I've lurked for a long time and have learned enough to take care of my pool all by myself (and it is a WHOLE lot nicer, since it is no longer locked up with stabilizer). That alone has saved me $50/month in idiot pool-guy fees, and my pool is no longer stabilizer locked requiring massive amounts of chlorine to boot

    I've done a bit with my plumbing so far, the idiots at the local pool store also installed a new pool pump (the last one died a heinous and sudden death, which was probably just the motor but I wanted an "energy efficient" pool pump so I sprang for the big $$$). But the new (~2 years old) pump is WAY too powerful for my pool and still sucks up obscene amounts of electricity. It is a Super II 1.5HP energy efficient (SP3015EEAZ so effectively 2hp). I want to change the pump since this thing costs me $100/month to run it a reasonable amount; and even more in the summer when we are actually using the darn thing (and electricity rates are up)!!! I do have a spa which we rarely use and actually the jets are too powerful already, and certainly doesn't justify the insane cost of running 2HP almost all the time. I also have too much head because the pool pipes although 2" are a tangled mess and there is no good way to correct the situation short of digging up all the concrete in the pool area. So it all seems perfect for a 2-speed pump. Yes, a Variable-speed would be even better but I'm trying to do this on the cheap, and would like to re-use the wet end of my still-very-new pump.

    So I believe I want to get a new 2-speed motor and also downsize at the same time. According to the SP3000X pump users manual at http://www.pool-pumps.com/pdf/Hayward-S ... Manual.pdf , the housing and everything is the same and I can change to a SP3010x152AZ motor (max-rated 1.5HP) if I also change the impeller, diffuser and wear ring. The AO Smith STS1152R is a compatible 56J 2-speed 1.5hp motor alternative that is cheaper. I think that all looked great except...

    I only have 115V feeding the pool equipment. Other outlets and equipment are also on this circuit, so I can't just convert it to 230V, which is what the SP3010x152AZ and STS1152R require. On the AO Smith website, it appears that the AO Smith B969 is an equivalent 115V 2-speed 56J 1.5HP motor to the STS1152R and thus the SP3010x152AZ. It sounds like it should work, if I match the impeller/diffuser/wear ring.

    Or am I completely confused and clueless???

    My other question is regarding whether I really need a fancy controller if I actually manage to get this new motor installed, or can I just leave it on low speed all the time unless I want to use the spa or vacuum (all which I'm happy to change over manually). Will this pump motor be able to successfully start up in low speed or do I need to pay out $$$$$ for a fancy controller?

    Oh, and one more question... do I even need 1.5HP for this set-up and how do I tell? The current pump/motor combo maxes out pressure when run through the spa with a brand new clean filter, which I think means the pump is too powerful for the restrictive spa. Is there any way to know if 1.5HP is still going to be too much? There isn't a 1hp 115V 2-speed pump, the next smaller size is 3/4HP, which is a lot less than we have now. Or could I just downsize the impeller instead? Or should I even get into that much complication??

    Thanks very much for any input anyone is willing to give!!!

    Kate

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    mas985's Avatar
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    Re: Changing 1-speed pump motor to 2-speed; slightly complicated

    A much less expensive option would be to just change the impeller/diffusor/ring. A 1.5 HP motor will work fine with a 3/4 HP impeller and won't use any more electricity than if you changed the motor as well. The current draw of a motor is determined by the impeller not the rating of the motor. So the 1.5 HP should draw no more power than a downsized motor.

    However, if you want two speeds, then you will have to change the motor as well.
    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: Changing 1-speed pump motor to 2-speed; slightly complicated

    Don't you think the lower draw on a 2-speed (0.2HP/4.4Amps on the B969) would save me enough to justify the price difference for the motor (~$300). I'm on Southern California Edison, so the pool costs $0.29/KWH for the summer. Also, do you think 3/4HP would be enough to run a spa and vacuum?

    Kate

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    svenpup's Avatar
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    Re: Changing 1-speed pump motor to 2-speed; slightly complicated

    I just did a similar conversion (check my signature for specifics) and am very pleased. I went with the TightWattII timer, but there is no reason you couldn't wire up a switch to control high/low.

    If you decide to go that route, don't forget to replace all the seals and o-rings including the shaft seal.
    TFP Method Advanced Intermediate
    • 17,500 gallons - In Ground - Plaster - Hayward Swimclear 3020 Cartridge Filter - Sta-Rite Max-E-Glas Main Pump upgraded with A.O. Smith B2980 E-Plus New Centurion Two-Speed Motor - Polaris 280 Cleaner with Polaris PB4-60 Booster Pump - TightWatt2 Timer - Taylor K-2006 Test Kit - Pool Pilot Digital Nano SWCG

    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

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    mas985's Avatar
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    Re: Changing 1-speed pump motor to 2-speed; slightly complicated

    Sorry, I missed the part about the spa jets. A 3/4 HP would probably more than enough for a cleaner assuming you can adjust the flow rates to the cleaner but for spa jets, probably not. A better option then might be just a motor swap out to a two speed so when you are not using the cleaner or spa, you can run on low speed.

    A 1 HP might be enough for the spa jets but I doubt it. It would probably be quite weak going through the filter. How many jets do you have and what is the recommended flow rate per jet?
    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: Changing 1-speed pump motor to 2-speed; slightly complicated

    Quote Originally Posted by svenpup View Post
    I just did a similar conversion (check my signature for specifics) and am very pleased. I went with the TightWattII timer, but there is no reason you couldn't wire up a switch to control high/low.

    If you decide to go that route, don't forget to replace all the seals and o-rings including the shaft seal.
    How's the B2980 treating you? I'm considering it. What impeller size are you using?

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