How to Read an AO Smith Pool Motor Label

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When the time comes to replace your pool pump motor the jumble of numbers and ratings on a motor can be overwhelming. This "How to" will guide you through which information is useful in your replacement pump motor search. We also provide tips on essential parts that should be replaced when installing a new pump motor.

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Step by Step

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Step 1

Tools you may need: 1. A cloth and cleaning solution, this is needed to remove any dirt or grime causing your pump motor label to be unreadable 2. A Shaft Seal or GOKIT when replacing your motor. Working seals and gaskets are vital to the health of your pool pump. A malfunctioning shaft seal will cause water from the pump to leak into your electrical motor causing it to fail prematurely. A GOKIT includes the complete set of your pumps gasket's and O-rings, including the shaft seal.

Step 2

In general there are two main labels on a pool pump; the pump label and pump motor label. Both can be used to determine the correct motor replacement but first we will focus on the motor label as it is the quickest and easiest to search. If your motor label is unreadable, later in the guide we will show you how to backtrack information off your pump to find the correct replacement. Quick Tip: The manufacturer of the pump motor and the pump itself are different companies even if the pump is brand new from the factory. For example, you have purchased a Hayward Super Pump, the wet end of pump where the water is housed is made by Hayward. The motor attached to that pump wet end was likely made by A.O. Smith, Century or Marathon.

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Step 3

An A.O. Smith pump motor label has a lot of different numbers and ratings that can have an appearance of alphabet soup at first glance. Let's narrow down the scope to just the information we will need to search for a new pool pump motor replacement. The list is as follows: Motor Model Number, Horsepower (HP), Service Factor (SF) and Frame (FR)

Step 4

When reading an A.O. Smith pump motor label the most pertinent information to aid you in finding a replacement is the "Motor Model Number." With this information alone you could find the exact match. As shown in the picture, an A.O. Smith motor may have two model number formats listed, either one can be used in INYO's pool pump motor search engine.

Step 5

The first format is one that follows the line of "UST1102", "ST1102" or "SN1102". The set of letters in the beginning denote the service factor rating of the pump. The "UST-" stands for an uprated motor and "ST-" means it is a full rated. The last four digits show its HP: "-1102" = 1 HP, "-1152" = 1.5 HP, "-1202" = 2 HP and so on. Type complete number (ex. UST1102) into INYO's product search at the upper right-hand portion of our site to find pool pump motor match

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Step 6

The second format of pump model numbers contains a prefix that is most commonly "C48", "C56", "K48" or "K56". This prefix is followed by four to nine letters and numbers which identify the specific motor. Type this entire number into INYO's product search to find the correct pump motor match. An example of this pump model number format: C48L2N134C1

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Step 7

If the Motor's model number is unavailable then we will have to use a combination of the pump label information and other available info on the motor label. The information needed off the motor label is the Horsepower (HP), Service Factor (SF) and Frame (FR).

Step 8

In most cases the Pump's manufacture label is located near the outlet port, location may vary depending upon the maker.

Step 9

On the pool pump label there should be two numbers listed, the serial and model. The pump model number can be entered into our product search engine; the result should provide the make, model and horsepower. Copy down this information and enter our pump motors section by selecting it in our “Shop by Category” sidebar.

Click Here to Find Your Replacement Pool Pump Motor & Gasket Kit

Step 10

In the Pump Motors section you will be asked for the manufacturer then the model. Your specific model may have two categories that list by your pump motor's service factor (SF). The motor's SF is listed on the label, this number will be in the range of 1.00 - 1.95. A SF of 1.00 to 1.27 is listed as an Up rated, anything over is Full rated. Please be sure you match the Service Factor of your pump as failure to do so will cause incompatibility between your current pump and new replacement motor.

Step 11

After checking all the previous information and have found a possible correct replacement, your last piece of info to check will be the Frame (FR). Most motors have a frame of "48Y", "56Y", "48J" or "56J". If your prospective replacement matches HP, SF, and FR then you have successfully found your motor replacement.

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Comments

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(1 to 40 of 258)

 Posted: 2/24/2023 

I also have a A.O Motor. But the Pump has the Numbers that are unreadable. The Motor is a 1081 Design Mod: C45k2n143c2c 3/4 HP. Want to replace motor and pump together. Its an old system. In ground Vynl Liner pool. Need something more efficient. What do you think? Can send oic is needed,
 Reply

InyoPools Product Specialist  Posted: 3/1/2023 

The C45k2n143c2c is not a valid Catalog Number, but the C48k2n143c2c is; it cross-references to a Century (A.O. Smith) .75 HP Full Rate Motor, Round Flange 56J Frame, Single Speed - Model ST1072. If the pump tag is unreadable, you'd need to identify the model using a part number from the strainer lid, pump basket, diffuser, or impeller. The first three options are acceptable for identifying the pump model, but you need help finding a pump with the same water output. But that motor is a .75HP full rate; they could have put it on a .75HP uprated or 1HP uprated pump. You need to get the part number from the impeller to ensure you get a similar pump in flow rate.
 Reply

 Posted: 2/8/2023 

Hi, I need a replacement for AO motor for the for the Heyward pool pump. MODEL#C48K2B143B1 SERIAL#09008CH HP-1 SF- 1.1 FR- 56J VOLT- 115/230 AMP- 15.0 / 7.5 THANKS
 Reply

InyoPools Product Specialist  Posted: 2/9/2023 

You'll need to verify that C48K2B143B1 is the correct model number; because it is not valid for any pool pump motor.
 Reply

 Posted: 2/9/2023 

Hi, I need a replacement for AO motor for the for the Heyward pool pump. MODEL#C48K2N143B1 SERIAL#09008CH HP-1 SF- 1.1 FR- 56J VOLT- 115/230 AMP- 15.0 / 7.5 THANKS
 Reply

InyoPools Product Specialist  Posted: 2/16/2023 

The correct replacement motor is the Century (A.O. Smith) 1.0 HP Up Rate Motor, Round Flange 56J Frame, Single Speed - Model UST1102
 Reply

Anonymous  Posted: 2/8/2023 

I have a century centurion type: CX, FR: X56J cannot find any info on this frame type. There is no screw hold down on the impeller and no way to keep the shaft from turning to remove the impeller. The back is not removable unless I remove 4 long screws and remove the armature. Any place to find info?
 Reply

InyoPools Product Specialist  Posted: 2/9/2023 

You'll need to provide the model. part, or catalog number of the motor for us to identify it. Not all motors are designed the same, so the method to lock the shaft in place varies. The 56J frame means it is a round flange with a threaded shaft. The 56J does not necessarily mean the motor shaft has internal threads for an impeller lock screw.
 Reply

 Posted: 5/19/2022 

Hello, I am looking for a.o.smith century pool motor, two speed, 1.5/2.5 HP, SF 1.3, Frame P56J, Type SXPM, part 7-193823-01. Can you help please
 Reply

InyoPools Product Specialist  Posted: 5/23/2022 

Can you verify that 7-193823-01 is the part number listed on the label? That code doesn't bring back any results.
 Reply

 Posted: 5/23/2022 

This is correct. Serial number BZ 04-14
 Reply

InyoPools Product Specialist  Posted: 5/25/2022 

I don't have a cross-reference to that motor's part number. What is the model number of the pump's wet end?
 Reply

 Posted: 5/12/2022 

Hi, I am looking for the replacement motor for a Vita Spa. It is an A.O. Smith motor, and the information from the label is as follows: Serial: BZ08-31 Part: 8-193107-01 Type: CXPM FR: R56Y HP: 4.0-.42 SPL SF- (blank) PH: 1 HZ: 60 RPM: 3450/1725 Volts: 230 Amps: 12.0/4.4 Thanks in advance for any help you can provide!!!
 Reply

InyoPools Product Specialist  Posted: 5/25/2022 

The correct motor replacement for the p/n 8-193107-01 is the Century 4.0 HP Thru-Bolt 56Y Dual Speed 230V Motor - B2235
 Reply

 Posted: 5/9/2022 

I need a replacement pool motor. Here are the specifications that I have found: HP 3/4 SF 1.5 FR N56CZ Century Pool and Spa AO Smith 1081 Serial 32309CH Type CS Thank you
 Reply

InyoPools Product Specialist  Posted: 5/11/2022 

We need the Model (MOD), Part (P/N), or Catalog (CAT) to identify the motor replacement.
 Reply

 Posted: 1/27/2022 

I'm trying to determine how old my pool pump is. The label says: Century Centurion A.O. Smith Serial BY09-05 Part 7 -177450-03 Type CX FR Y56Y
 Reply

InyoPools Product Specialist  Posted: 1/28/2022 

The information provided is for your motor, not the pump. Using the key in this article, How Old Is My Pool Pump Motor?, we can determine your motor was made in September of 2003. unless that is the original motor that came with the pump housing, I cannot determine its age.
 Reply

 Posted: 9/22/2021 

What size of starting capacitor do I need for a A.O Smith 1.5 hp pool motor, model number C48L2N134B1? Thanks.
 Reply

InyoPools Product Specialist  Posted: 9/22/2021 

The correct start capacitor for the C48L2N134B1 is the 610807-002
 Reply

 Posted: 8/15/2021 

Hello. Which start capacitor do I need for an A.O. Smith SQ1102 C48L2PA105C4? I'm assuming it's the start capacitor that needs to be replaced because when the power turns on, the motor makes a humming noise for about 5 to 10 seconds before the water starts filling up.
 Reply

InyoPools Product Specialist  Posted: 8/17/2021 

The SQ1102 (C48L2PA105C4) uses the Start Capacitor 161-193 MFD - BC-161. You may test the capacitor to determine if it is the cause of your motor issue using the steps in this guide - How to Test a Pool Pump Capacitor
 Reply

 Posted: 7/13/2021 

I need a new run capacitor for model number USQ1152 C48L2PA105C5. What is the part number of the run capacitor that I need?
 Reply

InyoPools Product Specialist  Posted: 7/14/2021 

Hello, the correct start capacitor replacement for your USQ1152 motor is the 161-193 MFD - BC-161
 Reply

 Posted: 1/13/2021 

Would you know which capacitor goes on a century B2983 1.5 hp motor ?
 Reply

InyoPools Product Specialist  Posted: 1/13/2021 

The B2983 1.5 HP dual speed motor uses 25 MFD - 628318-307 capacitor. You can also open the capacitor doghouse that sits on top of the motorto see the ratings on the capacitor's barrel.
 Reply

 Posted: 11/23/2020 

I believe I need a new start capacitor for my polaris pool pump. The motor buzzes every 3 minutes or so when the master control unit tries to start the system, but the pump has not been operational for the past few days. It is an AO Smith 1081 pool pump (motor label says it is a replacement for Polaris PB4-60 Booster Pump). I can't find the model #, but the label does indicate HP=3/4, SF=1.5, FRAME=N56CZ. Please let me know what replacement part to order. THANK YOU!
 Reply

InyoPools Product Specialist  Posted: 12/3/2020 

You motor requires the start capacitor, 124-149 MFD (BC-124)
 Reply

 Posted: 10/25/2020 

Motor HP question Pentair Challenger High Head motor replacement - it is a B843 Y56Y listed as 2.0 HP and 1.30 SF - total horsepower of 2.60 (MagneTek Century Centurion). I am confused by the information in the installation, operation & service manual (http://images.inyopools.com/cloud/documents/pentair-challengerpumps-manual.pdf). It has a horsepower column subdivided into F/FE* and A/AE. I believe my pump is a 1 1/2 F, 2 A based on the part numbers for the impeller, diffuser, etc., cross-referenced to the document. What are F/FE and A/AE?
 Reply

InyoPools Product Specialist  Posted: 10/27/2020 

I believe those columns are referring to full-rated and uprated motors, respectively.
 Reply

 Posted: 6/26/2020 

I'm looking for a dual speed motor to replace the current "Centurion for PAC-FAB, HP ---, part 7-168454-25, FR Y56Y, TYPE CX, RPM 3450, VOLTS 230/115". I think it is 2HP, but interesting not showing on the label. Any help is appreciated. Thanks.
 Reply

InyoPools Product Specialist  Posted: 9/24/2020 

the dual speed replacement motor needed for your B2858 is the Century 1.5 HP Square Flange 56Y Dual Speed Full Rate Motor - B2983
 Reply

 Posted: 5/25/2020 

I think my start capacitor is bad. Can you tell me what part number it is? Pump motor is a Hayward Northstar SP1615-Z-2-BC RPM: 3450/1725 Volts: 230 AMPS: 9.1/3.4 FR: P56J Type: CXPM Says it's an A.O. Smith Century Two Speed 1081 Pool and Spa Duty. This pump is for my pool which the Barracuda floor cleaner and skimmers tie into. Was hoping you could tell me what type of start capacitor I need without tearing the entire thing apart just to get the number. Thanks!
 Reply

InyoPools Product Specialist  Posted: 10/23/2020 

Your SP1615Z2BC motor uses the 21-25 MFD (BC-21) start capacitor.
 Reply

Anonymous  Posted: 4/29/2020 

I have an AO Smith Century Centurion Pool pump that is humming, I think I may need a new capacitor. With out having to open it up, can I figure out which capacitor I need with just the pump and motor information?
 Reply

InyoPools Product Specialist  Posted: 4/29/2020 

What is the part, model, or catalog number on your motor's label? A picture of the motor label would be most helpful.
 Reply

 Posted: 4/27/2020 

My booster pump "AO Smith model # 7-173840-23 just hums when I turn it on. After several seconds it trips the internal breaker. The shaft turns freely when I manually spin it from the end. Does this mean the capacitor is bad? If so, How do I find out which capacitor to replace it with?
 Reply

InyoPools Product Specialist  Posted: 10/27/2020 

it could be a bad capacitor, the only way to know for sure is to test it, How to Test a Pool Pump Capacitor. The correct run capacitor you need for the B625 motor is the 25MFD 370V - 628318-307
 Reply

 Posted: 4/11/2020 

i have a pentair pump but all i see is part 7-103262-20 w48y. im trying to find bearings
 Reply

InyoPools Product Specialist  Posted: 4/15/2020 

Can you recheck that motor part number? I cannot find any cross-reference to it anywhere.
 Reply