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How To Replace a Pool Pump Capacitor

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Save yourself the cost of a new motor. Check the capacitor first. When you turn on your pump and the motor produces a humming sound, the motor may be frozen so that it won't turn or you may have a bad capacitor. Check the capacitor. It can be replaced for a fraction of the price of a new motor. Note: Some motors have two capacitors: a run capacitor and a start capacitor. If so, check both.

Click Here to View Pump Motor Parts (Including Run & Start Capacitors, Bearings, and Switches) 



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Steps

Things You'll Need

Pool Pump Run Capacitor

Pool Pump Start Capacitor

Video

Step by Step

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Step 1

Turn off the power to the pool pump. For maximum safety turn the power off at the circuit breaker.

Step 2

Depending on the make of the pool pump, the capacitor will be under a hump cover on top of the motor, or it will be under a cover on the electrical end of the motor, or both. Some pumps have both a run capacitor and a start capacitor. The run capacitor will generally be rated at 15-50 MFD and 370 VAC. The start capacitor will generatlly be rated at 50-400 MFD and 125 or 250 VAC. This picture shows the location of the capacitor under a hump cover.

Click Here to View Pump Motor Parts (Including Run & Start Capacitors, Bearings, and Switches) 

Step 3

This picture shows the location of the pool pump capacitor at the end. In either case the covers are normally held on with two screws. Remove these screws to take off the cover and expose the capacitor. This capacitor is about the size of a roll of half dollars.

Step 4

Pool Pump Capacitors store an electrical charge that can shock you even when the power is off. Before removing the capacitor, discharge this energy by placing a screwdriver across the leads of the capacitor. CAUTION: Capacitors have been know to explode when shorted out. For your protection wear eye protection and place a cloth over the capacitor before shorting it out.

Step 5

If the capacitor is located at the end of the pool pump, remove the single screw that secures a clip holding the capacitor. Note how the plastic strip is positioned between the clip and the capacitor. It will have to be replaced in this position to keep the capacitor from shorting out on the motor. If the pool pump capacitor is on top of the motor, it should be free after you have removed the cover and the capacitor's leads.

Click Here to View Pump Motor Parts (Including Run & Start Capacitors, Bearings, and Switches) 

Step 6

Remove the leads to the pool pump capacitor. Note the placement of the leads so that you can restore them to their correct position when you reconnect them.

Step 7

Check the rating on the pool pump capacitor for replacement specifications. They will vary by manufacturer. Look for their MFD (or uf) and VAC specifications. For example, this one is a start capacitor rated at 124-149 MFD and 125 VAC. Try to replace the bad capacitor with an identical capacitor. If the exact capacitor is not available, you can use one with slightly higher capacitance. Do not use one with a lower rating.

Click Here to View Pump Motor Parts (Including Run & Start Capacitors, Bearings, and Switches) 

Step 8

Use a multimeter to verify that the capacitor is bad. Using the lowest ohms setting, touch the meter leads to the pool pump capacitor's terminals. If meter remains at 0, you know that the capacitor is bad. Check the new capacitor to verify it is good. First short out the terminals on the new capacitor to reset it. Then touch the meter leads to the capacitor terminals. If the capacitor is good, the meter will jump up to the other end than slower back off to 0.

Step 9

Connect the motor leads to the pool pump capacitor and secure the capacitor in place as required. Watch the placement of the plastic strip as mentioned above.

Step 10

Replace the cover.

Step 11

Reestablish power at the circuit breaker.

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(1 to 40 of 212)

 Posted: 5/23/2022 

I have a Raypak model RPAGP100. it just hums and doesn't run but will start when jump started with a screw driver on the shaft. What's the replacement capacitor for it?
 Reply

InyoPools Product Specialist  Posted: 5/23/2022 

I suggest looking at the capacitor for the ratings or part number. Unfortunately, there is no listed parts diagram for that proprietary motor.
 Reply

 Posted: 5/8/2021 

Hello, If I reconnect replacement capacitor to wrong motor wires, can I damage it? Capacitor connections are not labeled. I did not take a picture before removing old capacitor. If I reconnect new capacitor to wrong wires (orange and white) can I damage it? I assume so...So, how can I determine which wires go to which terminal on capacitor? Thanks!
 Reply

InyoPools Product Specialist  Posted: 5/13/2021 

It could damage the capacitor or the motor if wired incorrectly. What is the part, model, or catalog number on your motor's label? A picture of the motor label would be most helpful. Are the wires color-coded?
 Reply

 Posted: 8/29/2020 

I have a Century Centurion Part 7-193634-06. Can you tell me what capacitor to purchase?
 Reply

InyoPools Product Specialist  Posted: 8/31/2020 

Your 2.0 HP Round Flange 56J Full Rate EE Motor - B130 requires the 30 MFD (5VR0303) (2444) capacitor. 
 Reply

Anonymous  Posted: 8/20/2020 

I’m looking for a replacement for a Genteq 40uf 370vac run capacitor. It’s either part #24db400b370pa or 976b399ayp2.
 Reply

InyoPools Product Specialist  Posted: 8/20/2020 

If you visit our run capacitor section, you could find our  370v 40 Mfd (rd-40-370)
 Reply

Anonymous  Posted: 8/21/2020 

Do you have the dimensions for this? The old capacitor has a diameter of 1 3/4” and height of 2 3/16”
 Reply

InyoPools Product Specialist  Posted: 8/21/2020 

Length - 3-1/2", Diameter/Width - 1-3/4"  
 Reply

Anonymous  Posted: 7/13/2020 

I have a hayward superpump with A.O.Smith motor C48K2N143B1. it just hums and doesnt run. Whats the replacement capacitor for it? The one in the motor has this on its label: 680171-002, 161 -- 193 uF 110V. Thanks.
 Reply

InyoPools Product Specialist  Posted: 8/25/2020 

You can type that part number 680171-002 into our search to find the replacement: U.S. Seal Manufacturing Start Capacitor 161-193 MFD - BC-161
 Reply

 Posted: 6/7/2020 

I have an A.O Smith 2 HP pool pump and I think the capacitor is bad but I cant find it on the motor its model SP1520Z1ESC ...
 Reply

InyoPools Product Specialist  Posted: 10/23/2020 

The correct replacement capacitor for the SP1520Z1ESC is the 88-108 MFD (BC-86).
 Reply

 Posted: 5/30/2020 

Help! What size start and run capacitors do I need for a Max E glas P4EA6E-186L AO Smith motor U27-1234, K46K2PA105C1 115/230 volt, 75 kw, rpm 3450, fr-48Y, 60 hz, load 13.8/6.9 motor? Thanking you in advance for the reply.
 Reply

InyoPools Product Specialist  Posted: 10/23/2020 

Your K48K2PA105C1 (QC1072) uses the 20 MFD (RD-20-370) run capacitor.
 Reply

Anonymous  Posted: 4/20/2020 

My pump started smoking and popping.motor still turns b hand.
 Reply

InyoPools Product Specialist  Posted: 4/24/2020 

If the motor turns by hand, that just tells you the bearings haven't frozen up. But if your motor is smoking and popping, that is an electrical issue. Have you tested any of the motor circuitry since the almost fire started happening? Reference: Using the Proper Test Equipment to Troubleshoot Pool Motors
 Reply

 Posted: 1/29/2020 

I have a AO SMITH Century centurion with this data on the name plate. Cat B128 Serial 007083M Part 7-164303-23 Type CX FR M56J HP 1.0 SF 1.4 PH1 Hz60 RPM 3450 Volts 230/115 AMPS SF7.2/14.4 TIME CONT ENCL DP FORM KJM CODE J. It is in Nevis an island in the Caribbean. Can you advise on what capacitors to take down that are appropriate for this pump. Thanks in advance
 Reply

InyoPools Product Specialist  Posted: 2/10/2020 

The replacement run capacitor for the B128 - 1.0 HP Round Flange 56J Full Rate EE Motor, is the 25 MFD - 628318-307
 Reply

Anonymous  Posted: 1/5/2020 

I have a Century two speed motor - B984. It only hums when I turn it on low. It works fine on high. And it will run on low if I spin the motor or start on high and change to low. Could this be the capacitor?
 Reply

InyoPools Product Specialist  Posted: 1/6/2020 

This sounds more likely a bad switch or governor issue than a resistor. Is this a new or old motor? Has it been recently re-wired?
 Reply

Anonymous  Posted: 8/11/2019 

I have a Hayward super pump model # SP2607X10A and I was just wondering what run capacitor I would need?
 Reply

InyoPools Product Specialist  Posted: 8/13/2019 

We would need to know the part, catalog, or model number of the motor to identify the motor. The SP2607X10A  is the pump housing model number.
 Reply

 Posted: 7/20/2019 

I have a Pentair 340040 2hp pool pump. What run capacitor does it use? Thank you.
 Reply

InyoPools Product Specialist  Posted: 7/22/2019 

340040  is the model number of the pump housing, we would need to know the model number from the motor label.
 Reply

Anonymous  Posted: 7/10/2019 

I have a.o. smith ac motor number C48C34A72. I want to know which capacitor model i need to replace\
 Reply

InyoPools Product Specialist  Posted: 7/11/2019 

That number does not cross-reference to a part. Can you verify that is the correct identification number?
 Reply

 Posted: 7/9/2019 

I have an AO Smith 1.5 HP pump model C48L2N134B1. When first turned on it hums for a couple of seconds and then starts. I assume it's the Start capacitor which needs to be replaced. Can you let me know the part number. Thanks!
 Reply

InyoPools Product Specialist  Posted: 7/10/2019 

The start capacitor for the UST1152 is the 161-193 MFD (BC-161)
 Reply

 Posted: 6/19/2019 

I have a Polaris PB4-60 pool vacuum pump with a AO Smith motor 7-173840-23, Type: CS, FR: N56CZ, HP: 0.75, SF: 1.50 It’s doing the hum noise thing. Can you tell me if it has both a start capacitor and a run capacitor? Do you carry the start capacitor? Thanks so much.
 Reply

InyoPools Product Specialist  Posted: 6/19/2019 

The B625 booster pump motor only has a start capacitor which is the 124-149 MFD (BC-124).
 Reply

 Posted: 5/20/2019 

I took my capacitor off and when I came back the plastic had blown away. Is it okay to replace the capacitor w/o it being on there or is there something else I can use as a subsitute? Thx
 Reply

InyoPools Product Specialist  Posted: 5/20/2019 

The motor can be installed without that plastic sheet covering the capacitor. Its primary function is to act as a warning label, stating the end cover should be screwed onto the motor before operating.
 Reply

 Posted: 8/24/2018 

Hello Kelly - The booster pump motors only have a start capacitor. If you are getting proper voltage to the motor and the start capacitor is good, we recommend replacing the motor.
 Reply

 Posted: 8/23/2018 

Does a booster pump have both a start and a run capacitor? I replaced the one that's mounted on the outside, but didn't think to look for another. When my pump is supposed to be running, there's no sound or anything. It doesn't overheat. I've turned the bolt head where the windings are and it moves freely. There's power actually getting to it, but nothing actually happens...
 Reply

 Posted: 7/13/2018 

Hello Jacks - The run capacitor for the ST1152 is part number 5270-08. The start capacitor is part number 5270-11.
 Reply

 Posted: 7/11/2018 

I have an AO smith st1152 model # K48M2N110c1. My motor hums when I turn it on but won't start. Can you give me the part number for the start and run capacitors? thanks
 Reply

 Posted: 7/4/2018 

Just wanted to say thank you for this posting. Turned off motor for hour and a half and when I turned it on it just hummed. Thought my 4th of July was going down the tubes with no running pool and waterfalls all day. After reading this it took me one hour to get to the store and purchase a replacement capacitor and install it myself. Saved me about 5 days of waiting on a new motor and doing a motor replacement, plus it saved my 4th of July! Thanks!!!!
 Reply

 Posted: 1/29/2018 

Antionio Anselmi - The capacitor is a good place to start. The start capacitor for a UST1102 is 5270-14.
 Reply