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Thread: Replacing a single speed motor with a 2-speed

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    Replacing a single speed motor with a 2-speed

    In order to save on electricity for normal pool-water circulation, I would like to replace the motor on my Hayward Tristar with a 2-speed motor. I cannot go to a VS motor, as they only come in 230V flavors, and my pump-house/guest house share circuits on both legs of the 230V service, 60' from the main service entrance. The only 115V 3/4 HP 2-speed unit I can find (so far) is an A.O.Smith motor with the model #B973 (may be replaced with #C1109). This motor onlly comes in the 56J frame configuration, whereas the OEM Emerson motor has a 56Y frame. Will my Hayward Tristar wet-end accept a 56J frame?
    15K gallon in-ground gunite/plaster pool(58 year-old Anthony Bros.), 15'x30', depth 3-1/2'->8' . Hayward Ecostar pump. Hayward DE-3600 filter with Variflow 710XR50 1-1/2" valve. Polaris 380 cleaner & "the pool cleaner (suction)". Main-drain suction disconnected. New skimmer suction plumbing 2" PVC. Single return line 1" copper. Cleaner line 1-1/2" copper, re-plumbed in pump-house (PVC) for either suction or pressure. Hayward 3/4HP PB4 booster pump. Leslie's 260 BTU Coppertherm heater. All new suction interconnect plumbing 2". Return plumbing, filter-to-booster, 1-1/2". Single return to pool 1". All equipment located 2-1/2ft. above pool bottom level ( neg. 5ft. from surface ).

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    Mod Squad jblizzle's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    56J is not compatible with 56Y. But, a 48Y will work on the 56Y wet end.

    I agree, there seem to be very few 2-speed motors that are 115V. By your description I am a little unclear, why are you not able to wire a 230V motor (other than the hassle)? What is the service factor on your current motor?

    Try searching for this which is a square flange 0.75 HP 1.65 SF 2-speed motor: SQL1072R
    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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    Mod Squad Bama Rambler's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    AN AOSmith B2981 is a 3/4hp 2-speed 115v motor that's 56Y frame. You can find one Here
    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: Replacing a single speed motor with a 2-speed

    Dave, Thanks for the info on the A.O. Smith B2981. That motor apparantly also comes with an integral timer, and is designated B2981T. I'm afraid the "T" version is a bit too pricey for me though, at $563. It woul be nice to have the pump go to high-speed at the same time the pool-sweep booster pump turns on, but I would want to be able to go HS manually as well, when I back-wash the DE filter.
    Regarding the 240V situation, it is more than just a hassle. The first electrical segment, that fed the original 1947 house, was 100 amps, with 70 amps more added when the house was enlarged in 1952. When the guest house & pool were built in 1954, one 115V leg was taken off the original breaker box, and a 2nd leg was taken off the add-on box, both circuits brought to the 1954 additions underground, in a 1" galvanized pipe. Even if I could re-wire the entire "complex" ( a mish-mash combo of Romex, BX, EMT & aluminum conduit ), a single 240V breaker at the pump-house is not practical, as the Polaris booster pump works off one of the "remote" legs.
    FWIW, the service factor of the current Emerson motor is 1.85.
    15K gallon in-ground gunite/plaster pool(58 year-old Anthony Bros.), 15'x30', depth 3-1/2'->8' . Hayward Ecostar pump. Hayward DE-3600 filter with Variflow 710XR50 1-1/2" valve. Polaris 380 cleaner & "the pool cleaner (suction)". Main-drain suction disconnected. New skimmer suction plumbing 2" PVC. Single return line 1" copper. Cleaner line 1-1/2" copper, re-plumbed in pump-house (PVC) for either suction or pressure. Hayward 3/4HP PB4 booster pump. Leslie's 260 BTU Coppertherm heater. All new suction interconnect plumbing 2". Return plumbing, filter-to-booster, 1-1/2". Single return to pool 1". All equipment located 2-1/2ft. above pool bottom level ( neg. 5ft. from surface ).

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    Mod Squad jblizzle's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    FYI, Pump does not need to be on high speed for the booster pump. I am sure the built-in timer must allow you to manually change the speed ... but that is pretty expensive, considering you can find the SQL1072R for just under $300 delivered.

    That said, realize that I paid around $400 for my new 2-speed 1HP pump/motor combo; although the Tristar is more powerful.
    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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    mas985's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    They sell that motor without the timer too.

    http://www.polytecpools.com/aosmith-cen ... -6486.html
    Mark
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    UnderWaterVanya's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    Quote Originally Posted by Brewer
    FWIW, the service factor of the current Emerson motor is 1.85.
    With that SF you may find some 1hp SF 1.38 or less 2spd motors out there also.

    What about this one? USQ1102RR/B9801 see this link: http://www.pumpwarehouse.com/squareflange.html

    -sent with Tapatalk 2
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

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    Re: Replacing a single speed motor with a 2-speed

    I had looked at the 1072R ( the 1102R is the 1 hp version ), but opted instead for the B2981 ( the 1 hp is designated B2982 ) since they are E-Plus rated & eligible for a So Cal Edison rebate. After I get my new 2" skimmer line in tomorrow, & the pump-house plumbing straightened out, I will clean my DE filter, re-check head pressure & note any cavitation with my current pump, before going forward. The filter is rated at 48 gpm, but I would like to lower it to about 30 with a low-speed pump, and run it longer than I do now. Another option I am considering, if my pump still cavitates, is replace the 3/4 hp impeller with a 1/2 hp one ( that item is only about $12 ), but that will not provide any energy savings ( although it may prolong the life of the motor).
    15K gallon in-ground gunite/plaster pool(58 year-old Anthony Bros.), 15'x30', depth 3-1/2'->8' . Hayward Ecostar pump. Hayward DE-3600 filter with Variflow 710XR50 1-1/2" valve. Polaris 380 cleaner & "the pool cleaner (suction)". Main-drain suction disconnected. New skimmer suction plumbing 2" PVC. Single return line 1" copper. Cleaner line 1-1/2" copper, re-plumbed in pump-house (PVC) for either suction or pressure. Hayward 3/4HP PB4 booster pump. Leslie's 260 BTU Coppertherm heater. All new suction interconnect plumbing 2". Return plumbing, filter-to-booster, 1-1/2". Single return to pool 1". All equipment located 2-1/2ft. above pool bottom level ( neg. 5ft. from surface ).

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    Re: Replacing a single speed motor with a 2-speed

    Updating my plumbing re-do, My current pump will now move the water Ok, with only the new 2" skimmer line open, provided that the 1-1/2" port into the skimmer well is open. If that port is blocked, the current going through the weir is so strong a vortex is created & air is pulled into the pump basket. With the old 1-1/2" copper skimmer line & a blocked MD, the pump would cavitate & the filter pressure wouild drop to 10 psi. The clean filter pressure is now 24 psi (was 20 psi). I haven't checked the pressure with the cleaner line open & set for suction, since I want to let the Polaris get the accumulated crud out of the pool first.
    I need to determine my GPM flow, in order to match my the curves of prospective replacement pumps with my filter's design 48 GPM, and a target low-speed 30 GPM. If I understand the posts on that subject correctly, one can estimate the flow by adding up the "characteristic" dynamic head factors of the plumbing pipes albows & valves, plus feature factor such as heaters and fountains, then applying a "formula". I thought there were also simpler formula alternatives, using only filter pressure & pump inlet vacuum, or pressure, pump RPM and operating wattage. I would appreciate a redux of these methods, if possible ( Craig? ). I understand some folks have procurred vacuum gauges from auto-parts houses. I have a professional Robinaire air-condtioning service manifold I could use, but I would need to buy a Schrader-to-1/4"MNPT fitting, to match it to the pump's drain-plug.
    15K gallon in-ground gunite/plaster pool(58 year-old Anthony Bros.), 15'x30', depth 3-1/2'->8' . Hayward Ecostar pump. Hayward DE-3600 filter with Variflow 710XR50 1-1/2" valve. Polaris 380 cleaner & "the pool cleaner (suction)". Main-drain suction disconnected. New skimmer suction plumbing 2" PVC. Single return line 1" copper. Cleaner line 1-1/2" copper, re-plumbed in pump-house (PVC) for either suction or pressure. Hayward 3/4HP PB4 booster pump. Leslie's 260 BTU Coppertherm heater. All new suction interconnect plumbing 2". Return plumbing, filter-to-booster, 1-1/2". Single return to pool 1". All equipment located 2-1/2ft. above pool bottom level ( neg. 5ft. from surface ).

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    Mod Squad jblizzle's Avatar
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    Re: Replacing a single speed motor with a 2-speed

    Are you sure about the filter's design flow rate? A similar filter on the website lists 48 GPM as the design for PUBLIC application and a rate of 60 GPM for a PRIVATE application. I will say that generally, if the filter is the correct size for the pool and the motor is not very over-sized, then this is not usually a concern.

    I think a bigger concern might be the filter size. For a 15k gallon pool, we would generally recommend a DE filter ~42 sqft (or 220 sqft cartridge or 2.8 sqft sand). So your filter is about half the size we would recommend, especially given your location where you are not shutting down and emptying the filter for the winter.

    If you look at the flow rates for the 48 sqft or even the 36 sqft DE filters, the flow rates are well above what is typically achievable with normal pool pumps and plumbing.

    Also keep in mind that the filter will actually work better at lower flow rates, so a smaller motor (or 2-speed) for circulation would be cheaper to run and filter the water better.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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    Re: Replacing a single speed motor with a 2-speed

    Jason,

    Thanks for the input. I don't know why I assumed my filter was the DE-2400 version. I just checked my owner's guide, and took a measurement of the unit & found that the filter is actually the DE-3600 version, with a 72 GPM design flow rate ( still probably too small for the pool, but seems adequate for keeping it clean ). After I get the loose silt filtered out and the chlorine back up to the recommended level, I will tear the filter apart & check the condition of the grids. If any of them are damaged ( or show signs of eminent failure ), I will look into "upgrading" the unit to the 4800 size. That would entail replacing the filter head & dip-tube ( outlet elbow ), as well as all 8 grids. That will probably be pretty expensive, but not so much as replacing the entire unit, and will not entail re-plumbing the filter.

    Garry
    15K gallon in-ground gunite/plaster pool(58 year-old Anthony Bros.), 15'x30', depth 3-1/2'->8' . Hayward Ecostar pump. Hayward DE-3600 filter with Variflow 710XR50 1-1/2" valve. Polaris 380 cleaner & "the pool cleaner (suction)". Main-drain suction disconnected. New skimmer suction plumbing 2" PVC. Single return line 1" copper. Cleaner line 1-1/2" copper, re-plumbed in pump-house (PVC) for either suction or pressure. Hayward 3/4HP PB4 booster pump. Leslie's 260 BTU Coppertherm heater. All new suction interconnect plumbing 2". Return plumbing, filter-to-booster, 1-1/2". Single return to pool 1". All equipment located 2-1/2ft. above pool bottom level ( neg. 5ft. from surface ).

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