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Thread: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

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    Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    Last week, I put a post on the Forum entitled ‘Upgrading single speed Super Pump to 2-speed or VS‘ but haven't got any useful response; perhaps because of a too detailed description of my issue. So, I wonder if you would kindly respond to a more direct question below.

    Present situation: Present pool equipment is described in my signature (21K gal, IG plaster new 2010, 1 HP Super Pump, sand filter S-244T2, solar heating with HM-4000D controller, Hayward Cl Feeder CL220). This season, I am operating Hayward Super Pump with 1 HP single speed motor 24/7 because in the past I had to brush periodically green algae from the pool walls when operating it just 12 hrs a day.

    Issue: To minimize electricity cost while providing flow rate needed for effective sanitation, I am considering a replacement of the present 1 HP single speed motor with an appropriate 2-speed motor.

    Using the guidance found in Pool Pump Sizing and Super Pump performance data, I estimated the Total Head Loss and associated flow rates for Super Pump with 1 HP motor.

    (a) w/o Solar heating: Total Head Loss 40 ft 54 GPM at 3450 RPM 27 GPM at 1725 RPM
    (b) with Solar heating: Total Head Loss 50 ft 40 GPM at 3450 RPM 20 GPM at 1725 RPM

    Based on the above, I am thinking to get from Electric Motor Warehouse a Century motor B2975T
    1hp 3450/1725 230 volts 56J Pool Motor w/intergrated timer

    Question: Does the above motor selection make sense? Please let me know. Thank you.

    Jaro Pachner
    21K gal, IG plaster new 2010, 3/4 HP Super Pump with 2-speed AO Smith motor w/integrated 2Green timer, sand filter S-244T2, solar heating with HM-4000D controller, Dolphin M400 pool cleaner.

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    mas985's Avatar
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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    To minimize electricity cost while providing flow rate needed for effective sanitation, I am considering a replacement of the present 1 HP single speed motor with an appropriate 2-speed motor.
    Any pump or speed will accomplish that. It doesn't take much to circulate chlorine. The power of the pump is for other things such as spas, waterfalls and to a lesser degree skimmers and cleaners.

    But the B2975T is a full rated motor and it is a larger diameter than your current motor. The 1 HP Superpump uses an up rated motor. The motor you really want is the STS1072RV1. It is a full rated 3/4 HP but is the same "size" as a 1 HP up rated motor. It is also the correct diameter.
    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: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    Many thanks for your reply. I will need sufficient power to push water through my solar heating mounted on the roof (Total head loss 50 ft.) jaro

    Quote Originally Posted by mas985 View Post
    Any pump or speed will accomplish that. It doesn't take much to circulate chlorine. The power of the pump is for other things such as spas, waterfalls and to a lesser degree skimmers and cleaners.

    But the B2975T is a full rated motor and it is a larger diameter than your current motor. The 1 HP Superpump uses an up rated motor. The motor you really want is the STS1072RV1. It is a full rated 3/4 HP but is the same "size" as a 1 HP up rated motor. It is also the correct diameter.
    21K gal, IG plaster new 2010, 3/4 HP Super Pump with 2-speed AO Smith motor w/integrated 2Green timer, sand filter S-244T2, solar heating with HM-4000D controller, Dolphin M400 pool cleaner.

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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    Quote Originally Posted by Jaro View Post
    Many thanks for your reply. I will need sufficient power to push water through my solar heating mounted on the roof (Total head loss 50 ft.) jaro
    Again, most any pump will do that. I have a 1/2 HP pump running solar on a two story roof. No Problem.

    But understand that increasing the size of just the motor does nothing. It is the impeller that determines the size of a pump, not the motor. Of course the motor needs to be sized correctly for the impeller or it could overheat. Anyway, the correct two speed motor for your pump and existing impeller is the STS1072RV1.
    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: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    Thank you for clarification. Jaro

    Quote Originally Posted by mas985 View Post
    Again, most any pump will do that. I have a 1/2 HP pump running solar on a two story roof. No Problem.

    But understand that increasing the size of just the motor does nothing. It is the impeller that determines the size of a pump, not the motor. Of course the motor needs to be sized correctly for the impeller or it could overheat. Anyway, the correct two speed motor for your pump and existing impeller is the STS1072RV1.
    21K gal, IG plaster new 2010, 3/4 HP Super Pump with 2-speed AO Smith motor w/integrated 2Green timer, sand filter S-244T2, solar heating with HM-4000D controller, Dolphin M400 pool cleaner.

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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    Mark,
    I am back from the cottage and following up on your advise re replacement of a current 1 HP single speed motor CT1102 with a dual speed STS1072RV1. STS1072RV1 is a 2-speed motor but w/o a timer.

    Since I'd like to operate the Super Pump on high speed about 10h/day and on low speed 14h/day, I will need a timer to provide for such operation.

    One possibility is a 3/4 HP Full Rate Two Speed Motor with integrated timer - Round Flange (B973T, B2973T) 115V; web link A.O. Smith 3/4 HP Full Rate Two Speed Motor W/ Timer - Round Flange (B973T, B2973T) 115V - INYOPools.com

    This motor is larger in body diameter - 6.5”; I'd have to remove the mounting foot adapter underneath the motor. One question is the reliability of the integrated timer.

    I'd be grateful for your comments on B973T and also on a possible timer for STS1072RV1. Thank you.

    Jaro

    Quote Originally Posted by mas985 View Post
    Again, most any pump will do that. I have a 1/2 HP pump running solar on a two story roof. No Problem.

    But understand that increasing the size of just the motor does nothing. It is the impeller that determines the size of a pump, not the motor. Of course the motor needs to be sized correctly for the impeller or it could overheat. Anyway, the correct two speed motor for your pump and existing impeller is the STS1072RV1.
    21K gal, IG plaster new 2010, 3/4 HP Super Pump with 2-speed AO Smith motor w/integrated 2Green timer, sand filter S-244T2, solar heating with HM-4000D controller, Dolphin M400 pool cleaner.

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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    I really don't have any experience with those timers but my guess is it should out last the motor.

    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: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    UPDATE and a follow-up question for Mark (mas985).

    A couple of weeks ago, I replaced 1 HP motor by an A.O. Smith 2Green 3/4 HP Full Rate Two Speed Motor with integrated timer - Round Flange (B973T, B2973T) 115V. It was a good fit after removing the 'mounting foot adapter' from the Super Pump mounting foot. The timer interface is user friendly.

    Mark, I wonder if you could offer advise on optimum High Speed and Low Speed timer settings taking into account circulation requirements; consideration of electricity rates is secondary (Low: 7pm - 7am; Mid: 7am - 11am, 5pm - 7pm; High: 11am - 5pm). Thank you.
    21K gal, IG plaster new 2010, 3/4 HP Super Pump with 2-speed AO Smith motor w/integrated 2Green timer, sand filter S-244T2, solar heating with HM-4000D controller, Dolphin M400 pool cleaner.

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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    That is waaaay too much run time. Any reason you think you need that much. Have you read this: Pool School - Determine Pump Run Time

    For reference, my pool is about the same size as your and I run my pump for 1 hour on high (just for the cleaner) and 3 hours on low speed (mainly for the SWG and solar). And even that is too much run time.


    But what is "Mid" for a two speed motor?
    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: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    I took the low-mid-high times to be the electricity rates. If so, unfortunately the best time for solar heating is at the highest rates.
    ============================================================ ===========================================
    12,000 gal. IG Colorquartz, 1.65hp Sta-Rite with 2-spd motor, 300sf cartridge, disabled SWG, AquaLogic P4, Polaris 280, gas+solar, 6' sheer descent with dedicated pump

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    mas985's Avatar
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    Re: Replacement of 1 HP 1- speed motor with a 2-speed motor - PLEASE ADVISE

    I would just run it for solar. You shouldn't need anymore run time than that.
    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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