Need New Pool Pump Motor. Sizing?

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gitar

Active member
Jun 11, 2020
39
Boston Ma
Hi all. I have a 18,000G inground vinyl liner pool that I need to replace the motor on. The current motor is a Hayward Super Pump 1hp. It’s on its last legs as it continually trips the breaker and is over 8 years old. The sand filter model is a Hayward S160T with a GPM flow rate of 35 and max working pressure of 50PSI.
Three years ago we had our liner replaced and they cemented and covered the main drain. We now have 1 skimmer and 3 return jets in the pool.
I need to know the size motor I should purchase. It would seem like I could drop down to a Century 3/4 HP motor? I don’t know what else you need to calculate the motor size. I am aware if I change the motor size that I’ll need a new go kit and impeller. Can someone help me get this sized correctly. Thanks
 
What is the THP of the motor? Post a picture of the motor label. Also any labels on the wet end (pump).

Best option will be a VS motor.
 
mknauss said:
What is the THP of the motor? Post a picture of the motor label. Also any labels on the wet end (pump).

Best option will be a VS motor.
Click to expand...
Here is the label. Currently running on 115v. I am not looking to spend up to get a VS motor. We will be selling in a few years and need to buy some time. The replacement I’m looking at is linked below. Thoughts??

Century (A.O. Smith) 0.75 HP Up Rate Motor, Round Flange 56J Frame, Single Speed - Model UST1072 - INYOPools.com

Century 3/4 HP Round Flange 56J Up Rate Motor - UST1072
www.inyopools.com www.inyopools.com



1748480405083.jpeg1748480405083.jpeg
 
That motor might fit and work, but if it were me, I would at least get a 1 - 1.5 HP 2-speed. Running on high (single speed) is such a waste and robs you of your $$$. My Hayward Powerflo uses a similar motor, and I also am currently on 115V, but it's a 2-speed and I leave it on 24/7/365. I know you stated you aren't interested in going the VSP route yet, but you might keep an open mind. Since VSPs are mandatory across most of the US and have been around for a while now, the choices and prices have become quite competitive to standard motors.

I'll tag @1poolman1 though as he might have some additional thoughts.
 
Here's an option. Just installed this today.

IMPOWR Variable Speed Pool Pump Motor 1.25hp for $125 too risky?

Looking to get a variable speed pump motor to reduce energy costs and possibly keep my pool open through the winter. I already have a Hayward super pump, and an almost new super 2 pump housing so I don't need a pump and motor. I've seen issues with this impower posted and they appear to be out...
www.troublefreepool.com www.troublefreepool.com
 
gitar said:
Will it be adequate for my pool size and sand filter. I’m running 1.5” pipe and I see this stuff online about feet of head etc. I just want to make sure I’ll turn the pool over in 8-10 hrs.
Click to expand...
Turnovers are irrelevant. Please read this:

Turnover of Pool Water - Further Reading

www.troublefreepool.com www.troublefreepool.com

gitar said:
Hi all. I have a 18,000G inground vinyl liner pool that I need to replace the motor on. The current motor is a Hayward Super Pump 1hp. It’s on its last legs as it continually trips the breaker and is over 8 years old. The sand filter model is a Hayward S160T with a GPM flow rate of 35 and max working pressure of 50PSI.
Three years ago we had our liner replaced and they cemented and covered the main drain. We now have 1 skimmer and 3 return jets in the pool.
I need to know the size motor I should purchase. It would seem like I could drop down to a Century 3/4 HP motor? I don’t know what else you need to calculate the motor size. I am aware if I change the motor size that I’ll need a new go kit and impeller. Can someone help me get this sized correctly. Thanks
Click to expand...
Why do you want to downsize the motor?

If the old pump worked fine, why not just replace the motor or perhaps you may be able to repair the motor. Usually, motors will trip breakers because the bearings are going out but they can be replaced by a motor shop or yourself if you are handy.

Does the motor squeal or make other loud noises?

Does it trip the breaker when starting or some time after that?

If you are intent of downsizing the motor, then you will also need to downsize the impeller.

Another option is to replace the current motor with a VS motor as shown above although there may be better options. Not as expensive as a new VS pump but will save you money over the long run.
 
Last edited:
mas985 said:
Turnovers are irrelevant. Please read this:

Turnover of Pool Water - Further Reading

www.troublefreepool.com www.troublefreepool.com


Why do you want to downsize the motor?

If the old pump worked fine, why not just replace the motor or perhaps you may be able to repair the motor. Usually, motors will trip breakers because the bearings are going out but they can be replaced by a motor shop or yourself if you are handy.

Does the motor squeal or make other loud noises?

Does it trip the breaker when starting or some time after that?

If you are intent of downsizing the motor, then you will also need to downsize the impeller.

Another option is to replace the current motor with a VS motor as shown above although there may be better options. Not as expensive as a new VS pump but will save you money over the long run.
Click to expand...
Thanks for the advice! Answers to your questions are below…

Why do you want to downsize the motor?
A Given the size of the pool and my filter I thought it would be a better fit. I inherited the current pump from the previous owner.

If the old pump worked fine, why not just replace the motor or perhaps you may be able to repair the motor. Usually, motors will trip breakers because the bearings are going out but they can be replaced by a motor shop or yourself if you are handy.
A I am not very handy with motors. See other answer below.

Does the motor squeal or make other loud noises?

Does it trip the breaker when starting or some time after that?
A. It began to trip the breaker infrequently last summer. It would do it every so often and progressed to tripping every start and then to having to hit the side of the pump to get it to start. The motor is now 8-10 years old and has been exposed to the elements during winter except for a tarp.

If you are intent of downsizing the motor, then you will also need to downsize the impeller.
A Understood

Another option is to replace the current motor with a VS motor as shown above although there may be better options. Not as expensive as a new VS pump but will save you money over the long run.
A someone said something about 2 speed pump motors. I’m trying to keep this economical as we may move in the next few years. I know Century took over AO Smith and have always used a Hayward AO Smith motor. In your opinion is Century an okay replacement? Why are the Hayward single speed pumps so much more money.
Thanks again for the help.
 

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gitar said:
A. It began to trip the breaker infrequently last summer. It would do it every so often and progressed to tripping every start and then to having to hit the side of the pump to get it to start. The motor is now 8-10 years old and has been exposed to the elements during winter except for a tarp.
Click to expand...
Sounds like the bearings are out on the old motor.

gitar said:
A someone said something about 2 speed pump motors. I’m trying to keep this economical as we may move in the next few years. I know Century took over AO Smith and have always used a Hayward AO Smith motor. In your opinion is Century an okay replacement? Why are the Hayward single speed pumps so much more money.
Thanks again for the help.
Click to expand...
Century is just a rebranding of AO Smith after the purchase by Regal Beloit. They are fine for a replacement motor but there are other brands such as Nidec that would work as well.

However, you might find that a VS motos is not that much more than a two speed motor. The one in post #8 is actually much less than most two speed motors but long term reliability has not been proven on that one either.

Century also makes a VS motor:

Century (A.O. Smith) V-Green EVO 1.30 HP Up Rate VS Motor, Round Flange 56J Frame, Variable Speed - Model EVC130 - INYOPools.com

Century (A.O. Smith) V-Green EVO 1.30 HP Up Rate VS Motor, Round Flange 56J Frame, Variable Speed - Model EVC130
www.inyopools.com www.inyopools.com
 
gitar said:
That is great information! Thank you. Should I downsize to 3/4hp based on the pool and filter size GPM? Thanks
Click to expand...

Not if you plan on going with a VS motor. Note the VS is only $100 more which you will probably make back in energy savings in just a few seasons.
 
For a comparison:

SuperPump 2 speed on low speed uses around 300 watts.
SuperPump VS on the same speed/GPM as the 2 speed uses around 150 watts.

At $0.28/kwh, you only need about 2400 hours of operation to break even or at 8 hrs/day, about 10 months of operation.
 
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