How To Replace a Pool Pump Capacitor

WRITTEN BY:  Inyo Pools

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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.

Video

Step by Step

Top

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.

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.

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.

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.

Comments

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(1 to 40 of 167)

Inyopools  Posted: 08/28/2017 12:22 PM  Inyo Product Specialist

ebv128 - Check that the new capacitors have the same specs as the original capacitors. Then retrace your replacement steps to see if there was anything else you may have done to affect the switch. Check the switch.


ebv128  Posted: 08/26/2017 13:45 PM 

With the help of the video, I have replaced both the start and run capcitors on my Sundance Palermo 2005 2-speed emerson motor. However, now the first speed is not as strong as it used to be, and i need to push the button twice for the high speed to kick in and then off, and then on for the first speed to kick in. Sugggestions, please


Inyopools  Posted: 08/14/2017 12:38 PM  Inyo Product Specialist

Anónimo - I'd try replacing the capacitor(s) first. You may have two capacitors, a run, and a start capacitor. They are the easiest repair. I can't help you much without knowing what pump you have. Do a search on our website for your pump. Once you find the pump's product page, look for the link to it user's manual. There should be a trouble shooting section at the end of the manual.


Anónimo  Posted: 08/10/2017 1:01 AM 

I have a pool pump that stopped working recently. There is a window on top of the motor where you can see how long it will run (2hr, 4hr, 6hr...24hr) and there is a timer button to select how long you want it to run and an on/off button. When the motor is plugged in, the light indicator for the hour selection blinks on and off, telling you that it is off. When you push the on/off button, it stops blinking (indicating that it is on) and the motor usually runs. The problem is that now, when it is plugged in, the light blinks and everything like normal, but when you turn it on, the light stops blinking but the motor doesn't run like it would usually do. There is no humming, no sound at all coming from the motor. The light indicator acts like it normally would, but the motor simply doesn't run or make a sound. Would the capacitor be the issue, or is it another problem. I can provide details if needed, please let me know and I hope to hear a response soon.


Inyopools  Posted: 08/07/2017 13:00 PM  Inyo Product Specialist

Ed - If the motor is humming, it's a good bet that one of the capacitors is shot. Try replacing the start capacitor first, behind the back cover, then replace the run capacitor. on top.


Ed  Posted: 08/06/2017 15:37 PM 

I have a Hayward 2.5 super pump that quit while running, will not start and makes a humming noise. There is a capacitor on top is there also a capacitor behind the cover on this model. thanks


Inyopools  Posted: 08/05/2017 13:22 PM  Inyo Product Specialist

Terrell - I did not receive the picture through this comment page. Could you provide the motor's CAT and Part # along with it's HP, SF and amps?


Terrell  Posted: 08/02/2017 13:47 PM 

My capacitor went out, but my motor is only three years old. Here is a picture of the label: The Label reads:
Century Centurion
Switchless Motor
No Switch * No Governor
2514514-001

Can you tell me what kind this is and if so, do you carry it?


Beachgirl629  Posted: 07/18/2017 14:13 PM 

I have swimming pool pump that is being used as a well pump. I was told the electrical start component has went out. I would like to send you a pic but there is no option. My starter capacitor does not look like the ones you are showing. Do I need to replace whole unit?
I was having to plug it in everytime I used it. Then one day when I plugged it in, it went proof at the junction box.


Inyopools  Posted: 07/13/2017 14:44 PM  Inyo Product Specialist

Anonymous (UST1152) - According to our motor rep: "The capacitor only sees one-half the circuit, so it can use the 110-125VAC capacitor".


Inyopools  Posted: 07/13/2017 13:26 PM  Inyo Product Specialist

Anonymous (UST1152) - Thank you for your feedback. You make a good point. I will verify this with our motor rep.


Anonymous  Posted: 07/12/2017 17:40 PM 

Hello,

In the following exchange your recommendation for a 110-125VAC Start Capacitor has me concerned... Since the UST1152 can be hooked up in a 230VAC configuration shouldn't the Cap be rated at least that high?

RJL Posted: 07/05/2017 18:55 PM Latest

We have an A.O Smith 1 1/2 HP motor for our in ground pool. On the top of the label it says "UST 1152" and along side the motor mod tab on the cover it lists it as "C48L2N134C1", Ser 10010CH. Anyway when I got home from work I noticed there was no water movement in the pool. It's scheduled to start up at 1000/am. No hum coming from the pump. This was at about 300/pm or so. I turned the switch off and on again it it hummed for a few seconds, 10 or so and turned off. How many capictors on this model? Does it sound like a capictor issue?

Thank you, JAM


Inyopools Posted: 07/09/2017 12:34 PM Latest Inyo Product Specialist

RJL - Replacing the start capacitor on your motor is a good place to start. The start capacitor for a UST1152 motor is Capacitor, MFD 161-193 (BC-161) 110-125VAC.


Inyopools  Posted: 07/11/2017 12:54 PM  Inyo Product Specialist

Slamfam - I'd check to make sure you have the right capacitor. Tha start capacitor you bought is for either a 1HP or 1 1/2HP uprated motor, like a UST 1102 or a UST 1152. Make sure your wire connections to the pump are tight. Make sure the motor shaft spins freely. Check that the governor is not stuck open. Other than that, you may have a short in the motor windings, which generally means a new motor.


Slamfam  Posted: 07/10/2017 18:47 PM 

I just replaced the capacitor on a Hayward Super Pump (like the one in the video). When I turned on the power, it tripped the breaker. The new capacitor is rated the same, 161-193 MFD, 110-125 VAC. Is it possible the new capacitor is bad or am I looking at a new pump? The problem started Saturday the 9th. I turned off the pump to backwash the pool and when I turned it back on it did not start but was humming so I started with the capacitor. Any help would be greatly appreciated.


Inyopools  Posted: 07/10/2017 13:38 PM  Inyo Product Specialist

mcol75 - The capacitor for you motor, 7-187582-02, is Capacitor, Run 370v 35 Mfd (rd-35-370).


mcol75  Posted: 07/09/2017 16:45 PM 

Hi our capacitor is out for our 2.0 HP pump (AO Smith 7-187582-02). I cant read the size info on it anymore. What size capacitor should I order?


Inyopools  Posted: 07/09/2017 12:34 PM  Inyo Product Specialist

RJL - Replacing the start capacitor on your motor is a good place to start. The start capacitor for a UST1152 motor is Capacitor, MFD 161-193 (BC-161) 110-125VAC.


RJL  Posted: 07/05/2017 18:55 PM 

We have an A.O Smith 1 1/2 HP motor for our in ground pool. On the top of the label it says "UST 1152" and along side the motor mod tab on the cover it lists it as "C48L2N134C1", Ser 10010CH. Anyway when I got home from work I noticed there was no water movement in the pool. It's scheduled to start up at 1000/am. No hum coming from the pump. This was at about 300/pm or so. I turned the switch off and on again it it hummed for a few seconds, 10 or so and turned off. How many capictors on this model? Does it sound like a capictor issue?

Thank you


Inyopools  Posted: 06/26/2017 11:10 AM  Inyo Product Specialist

Anonymous (3400vs) - Not sure if the 3400VS has a start capacitor, but if it does, replacing it would be a good place to start. The capacitor would be under the end electrical cap if it has one.


Anonymous  Posted: 06/23/2017 15:05 PM 

My hayward 3400vs motor won't start..could Ithis be the start capacitor?


Inyopools  Posted: 06/20/2017 9:08 AM  Inyo Product Specialist

Splashed - Most pool motors capacitors cost between $15 and $30. See Capacitors. So I'd recommend changing the capacitor(s) before buying a new motor. If your repairs are going to take a couple of days, you might throw in a couple bags of shock treatment especially if your pool is starting to turn a little green. Most pools only have 1 skimmer.


Splashed  Posted: 06/19/2017 9:03 AM 

So, our Hayward pump is humming, and from what I sm learning, if we want to replace the capaciter, that is a good sign. But heres what. From my research, they run about 150 estimated each and a brand new pump is 325. My experience with most engines or electrical parts is if you replace one, the other is usually not far behind. Our pump motor is an AO Smith and to replace with a Hayward, would be less expensive than buying two capaciters, and a lot less work. One of my concerns is what about why this happened? Is there a clog or problem? We have to find that. We cannot backwash to clean sand, ir flush a line, etc., so I guess this is a good time to replace sand. Should we load the pool with anything to keep anything from growing while we get tbe parts and fix this? Also we have only one skimmer... is that protocol for most pools? We are novices, we bought this house, this pool, these issues. Grrrrrr


Inyopools  Posted: 06/13/2017 23:12 PM  Inyo Product Specialist

Ugggh - Your O-173840-23 motor is an AO Smith Booster Pump Motor - B625. It has one start capacitor on the top of the motor, Capacitor 124-149 Mfd 125v (BC-124).


Ugggh  Posted: 06/12/2017 20:52 PM 

I have a AO Smith Century Pool O-173840-23 pool pump for my bottom sucker. Hums then shuts off. It has a capacitor on the top. Does it have one in the housing too?


Inyopools  Posted: 06/01/2017 11:50 AM  Inyo Product Specialist

Brenda - Unfortunately, we do not carry this pump/motor and I can't locate in on the internet with the numbers you provided. If this motor has a capacitor, it would be under the electrical cap on the end of the motor. Look for burn marks. Replace the capacitor, is applicable. If no luck, your motor probably needs to be replaced.


Inyopools  Posted: 05/30/2017 16:37 PM  Inyo Product Specialist

JenRM - This motor, 7-184981-23, is an A.O. Smith Motor 56J Threaded, Up rated 1 Hp (b228se). It has no start capacitor, only a run capacitor - part #, 5270-05, 370V, 30 Mfd. Check the run capacitor for damage. They usually bulge out at the ends. If it looks good, your motor probably has a short in the windings and you may need a new motor.


Inyopools  Posted: 05/29/2017 20:02 PM  Inyo Product Specialist

Glo - This motor only has a run capacitor, no start capacitor. The run capacitor is mounted on top of the motor under the bump. I'd try replacing the run capacitor first but the humming might be due to a short in the windings which generally means a new motor.


Inyopools  Posted: 05/29/2017 19:02 PM  Inyo Product Specialist

Clint - If this motor has a start capacitor, it will be behind the electrical cover like in this guide.


Brenda  Posted: 05/29/2017 16:50 PM 

I have a waterway wet end above ground 2hp pool pump. It's humming, and kicks the breaker. It won't start up, and I've even tried jump starting it. I can turn the screw with a screw driver, but no luck starting it. Is it the run capacitor? Here is the info regarding model number, etc:
Model# SD-20-1N11CD
Part# PX1200-6


JenRM  Posted: 05/29/2017 11:25 AM 

Hi,I have a sp2607x10 Hayward pump with a 1Hp
motor, replaced 8 years ago, part 7-184981-23. The info I found in the motor manual says the capacitor is '2443' but I can't relate that back to something I can buy. I see 370vac and 6% and 307 on the capacitor (I don't want to remove it until I have the replacement). Can you help me with what capacitor I need to get for the replacement? The motor just hummed when I tried to start it this year and I can't feel any debris in the impeller so I'm hoping it's the capacitor.


Glo  Posted: 05/27/2017 23:06 PM 

I have n A.O. smith part 7-165199-05. 1HPpool pump. I am trying to get into the capacitor but my screws are stripped. Does this model have a start and run capcitator? Only hums when I start it. Do I also need to get into the motor? Would that be the run capacitor on the inside and the start on the outside? Might need a manual and two capacitors. Please advise.


Clint  Posted: 05/26/2017 21:50 PM 

I have a Ningbo Tuozhan 1 HP motor Model number RS4G24213L and hums when to turn on the power but I can get it started by using a screw driver to spin the motor shaft end. Can you tell me if this motor has a start capacitor and where is it located? I'd appreciate your help. Thank you very much.


inyopools  Posted: 05/19/2017 15:36 PM  Inyo Product Specialist

David - Your pump motor uses a 25 MFD, 370 Volt run capacitor. It does not have a start capacitor.


David  Posted: 05/18/2017 10:58 AM 

Ok, my turn..... I have a Sta-Rite Max E pump model # P6E6C-204L. Can you tell me how many capacitors it has and what the correct replacement(s) would be?

Thanks in advance.


Inyopools  Posted: 04/21/2017 14:36 PM  Inyo Product Specialist

Raymond - I would wire the capacitor as shown. It connects to three different circuits including a startup circuit. See Step 8 in our guide on "How the Common Capacitor Start Pool Motor Works".


Raymond  Posted: 04/20/2017 15:09 PM 

Replacing a destroyed start capacitor 161-193 on a Sta Rite pump motor C48L2PA105. Need assistance in hooking up the three leads (2 yellow and 1 red/white). your photos indicate yellow leads attach to same set of terminals and red/white to other set. Does it matter which set of termnials they are hooked to? Thanks
Ray


Inyopools  Posted: 03/27/2017 11:58 AM  Inyo Product Specialist

NHCannon16 - Try placing the foam on top of the capacitor. Also make sure that your replacement capacitor at least matches the old capacitor. In this case, it sounds like 370V 30uf. If you pump motor is continually burning up capacitors, try using the next one up in size. Capacitors are susceptible to power variations or increases. If you can't control your system power, you may need a capacitor with a little higher rating - 370V 35uf.


NHCannon16  Posted: 03/26/2017 17:24 PM 

I just replaced the capacitor on my Pentair Challenger II and the pump ran for less than 30 seconds and then shut down. Smelled a burning smell and I turned off and flipped the switch on the fuse box. I replaced a 30uf with a 30uf. The capacitor is on top of the motor in the "hump" and when I replaced it, the foam cover was not sitting on top of the capacitor, but placed beneath it. In pictures online of other motors that foam piece is above the capacitor. Could it have shorted out on the metal cover? Any ideas as to what to do next?


James Blilie  Posted: 03/06/2017 14:55 PM 

Thank you very much for your help! Order incoming shortly.


Inyopools  Posted: 03/06/2017 12:05 PM  Inyo Product Specialist

Richard - How do you switch between the two speeds? I would check the hi/low switch or the wiring from the switch to the motor.