A.O. Smith 2.5 H.P Pool Motor Round Flange 56J - UST1252



Part # UST1252

By A. O. Smith

  4.78 Average  



Part # UST1252

Warranty 1 Year

Dimensions 16" L x 8.5" W x 6.5" D

Alternate Part #'s 12020, 164135, 177022, 184951, 5KCR39UN6181X, 90118597, B231, B231SE, C1149, EB231, JH25UP1, K48N2N106, K48N2N106A1, K48N2N106A3, K48N2N106A9, K48N2N106C2, K48N2N113A6, SP1620Z1M, SP1620Z1MBK, UST1252, V12020

Product Description

Voltage 230, Max Amps 230V = 11.2, Single Speed, Round Flange, RPM = 3450, Threaded Shaft, Frame = 56J Used on the following models: Hayward Max Flow, Hayward Super Pump, Hayward Super II, Hayward Northstar and Jacuzzi Magnum pumps.

Motor Dimensions Motor Dimensions
Motor Image Motor Image

Product Specifications

Motor Name:
2.5 HP UST1252 Replacement Pool Motor
2.5 HP
3450 RPM
208 - 230 V
12.6/11.4 amp
Service Factor:
Total HP:
2.75 HP
Stock #:
Overload Protector:
Dimension Letter:
13 - 1/16 in.
Commonly Used On:
Hayward Max Flow, Hayward Super Pump, Hayward Super II, Hayward Northstar and Jacuzzi Magnum

?     Asked on 5/30/2016 by Mike

I am looking to replace a pool motor UST 1252. Found in on your webpage along with tune-up kit. I was having pump leak problems at the seam between pump and main housing. Thinking of replacing at same time. Do you have a complete kit or only parts ?

A     Answered on 5/30/2016 by InyoPools Product Specialist Patrick P.

Hi Mike, we may have a kit but we would need to know the make and model of your pump. This should be something like Hayward Super Pump, Hayward Super II, Jacuzzi Magnum, etc.. Could you please email back with your pump details.

?     Asked on 7/14/2015 by Ken

I have a 2 year-old UST1252 motor. I believe the start capacitor is failing - perhaps the run capacitor as well. The pump generally does not start (hums and then shuts down and/or breaker trips) the first time after sitting for a while. Flow seems good once it runs and the impeller seems to move freely (I have only reached in through strainer side, have not removed the pump (yet). All that said, can you tell me the size/ratings for the capacitors? Thanks! Ken

A     Answered on 7/16/2015 by InyoPools Product Specialist Lennox H.

Hi Ken, The A.O. Smith (UST1252) uses a Run Capacitor 30 MFD 370V (5VR0303) and Start Capacitor 36-43 MFD 120V  (BC-36).

?     Asked on 1/19/2012 by Guest

I'm trying to replace the motor on my pool pump but all these numbers and abbreviations on the motor label are really confusing me. What do they mean?

A     Answered on 1/19/2012 by InyoPools Product Specialist Patrick P.

Replacing a pool pump motor is not as difficult as it seems. You can try looking here. If you need help figuring out what the information on your label means. If you are still having difficulty figuring it out you can call us at our toll free number or you can send us a photo of your motor label here.

?     Asked on 1/18/2012 by Guest

I'm trying to find a replacement motor for my pool pump but my model number doesn't match what you have listed as the model number. My model number begins with a C48 and yours begins with an SP. Please help.

A     Answered on 1/18/2012 by InyoPools Product Specialist Patrick P.

What we have listed on our chart pages is the pump model number. The model number you have will just identify the motor. If you look on the plastic housing on the pump there should be a sticker which will have the pump model number. You can usually find this by the discharge port on the pump. Once you locate it you can choose the correct replacement motor. Be certain to change the shaft seal and gaskets as needed. You can use our >How to guide if you need help. 

?     Asked on 1/12/2012 by Guest

Why should I purchase a Tune Up Kit?

A     Answered on 1/12/2012 by InyoPools Product Specialist Patrick P.

A Tune Up Kit includes all of the essential replacement seals and gaskets for the pump. The seals and gaskets should be replaced when installing a new motor on your pump. New seals will prevent the pump from leaking water or losing the prime. A Tune Up Kit will protect your motor and ensure that the pump is working efficiently.

?     Asked on 1/12/2012 by Guest

Why do I need to purchase a new shaft seal?

A     Answered on 1/12/2012 by InyoPools Product Specialist Patrick P.

We strongly recommend replacing the shaft seal. The purpose of a shaft seal is to prevent water from running down the shaft of the motor and into the motor housing. Water will damage the bearings and cause the motor to fail. A new shaft seal should be installed whenever a motor is replaced. The motor manufacturer can deny the warranty if the motor fails to due to water damage from a faulty shaft seal. To find your shaft seal you will need to visit our Pool Pump Parts Page or the Spa Pump Parts Page and select your make and model.

?     Asked on 1/11/2012 by Guest

What is Service Factor?

A     Answered on 1/11/2012 by InyoPools Product Specialist Patrick P.

Service Factor(SF) is a multiplier that when multiplied by the horsepower of the motor indicates the total permissible horsepower loading that may be carried when the motor is operating at rated voltage and frequency. The most important thing to remember when replacing a motor is that the replacement motor's horsepower times its service factor must be equal to or greater than the original motor's horsepower times its service factor. The Service Factor rating can be found on the motor label. See Step 4 of our How to Read a Pool Motor Label guide.


Review Summary

  (Average 4.78 out of 5 stars)
22 Rating
5 star:
4 star:
3 star:
2 star:
1 star:

The Most Helpful Review

The Most Recent Reviews