motor replacement: single speed or variable speed?

  • Last Post 16 March 2019
  • Topic Is Solved
DavidGuirl posted this 12 March 2019


I have a motor that has died on me; i've replaced the capacitor and it still won't work. it's about 8-10 years old so i think it's finally time to replace it. The impeller spins freely but just won't kick into high gear. I have a 38,000 gallon pool in South Carolina with a Jacuzzi salt system installed last year. I would like to save some money on operating costs. I currently run the motor about 10-12hours/day in the peak season, and 4-6hours/day in the winter. i do not cover the pool in winter. there is also a booster pump that i run 2 hours/day for the Polaris.

I guess my two main questions: given the above description of my pool, how much money would i expect to save using a variable speed motor? how do i determine what speed and hours/day to run the motor to get the most efficient?

I have a US Motors 1.5HP 1.3SF 3450RPM 56J. I think it's a Hayward Super Pump (square top not round). 

I can't seem to find the direct replacement for a single speed motor with the same specs. I found the dual speed AO Smith 1.5HP B2977. 

But I am reading about the more efficient variable speed motors, like the AO Smith 2.7HP ECM27CU




Order By: Standard | Newest | Votes
InyoRob posted this 12 March 2019

Hello David - The most energy efficient option is the variable speed motor. The ECM27CU would be the correct variable speed motor for your Hayward Super Pump.

The energy savings will depend on how you set the pump up. Running it at lower speeds will provide the most savings. The goal is to turn the body of water over once a day. To figure out the gallons per minute at each speed, we recommend installing a flowmeter. This way you can test the pump at different speeds and see exactly how many GPM is produced.

Check out our article titled "Best Setup for a Variable Speed Pool Pump".

DavidGuirl posted this 12 March 2019

thanks! i'll check out that article. i did read the other article about "5 reasons to get a variable speed pump". unfortunately the price just went back up, costing me another $45 if i order now ...

InyoRob posted this 12 March 2019

We had a recent price increase from our vendors. Let me know exactly what you want to order and I can email you a quote with a discount.

DavidGuirl posted this 12 March 2019

great thanks! I would also like to replace the motor mount plate, as it does not look good. and the bolts. i think these are correct - are the bolts stainless steel so the salt won't destroy them? is this part supposed to get wet?

SPX1600F5 and spx0125z44

motor mount plate

InyoRob posted this 13 March 2019

We emailed you a quote. I added a heavy duty shaft seal. That will protect you from the corrosion in the picture above.

The bolts are stainless steel. You shouldn't see the same problems with the new shaft seal.

DavidGuirl posted this 15 March 2019

thanks for all your help; i ended up ordering the single speed motor after doing some more research. once i get everything operational again, i'll buy the flow meter and check the actual GPM, then set the timer to only run for the time required to turn the pool over once. i figure if the pump is off, then i'm saving the most money  

InyoRob posted this 16 March 2019

Thanks for the update. Every pool should have a flow meter. It makes life a lot easier.