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) 


Step by Step


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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 Posted: 4/26/2012 

Removed end cover on Hayward 1/2hp super pump and no capacitor. Do all motors have a capacitor? Any thoughts?

InyoPools Product Specialist  Posted: 3/11/2012 

nakama- Unfortunately we do not have that information. Please call the manufacturer Pentair at 1-800-831-7133 and their techincal staff should be able to help you.

 Posted: 3/7/2012 

I forgot to note the location of the wires on my capacitor. Is there a way of finding out which leads go to which terminals on the capacitor? I have to yellow wires and one white on my 1hp Challenger Pump. Thanks

InyoPools Product Specialist  Posted: 3/3/2012 

We are working on this. Until then you can copy the whole guide over to Word and then print it from there.

Anonymous  Posted: 2/29/2012 

How come i cant print the whole article on any of the how to articles only the 1st page prints?

 Posted: 1/2/2012 

Thank you for the information on How to Replace a Pool Pump Capacitor

InyoPools Product Specialist  Posted: 9/8/2011 

garno - You will find our list of capacitors on our website under "Pool Parts" then 'Pool Pump Motor Parts"

 Posted: 9/5/2011 

Where and how do I ORDER a NEW CAPACITOR...For a Hayward 11/2 HP Super pump????

InyoPools Product Specialist  Posted: 8/9/2011 

Sounds like something is shorting out your capacitor. Make sure the plastic strip is in place (see step 9). If that's not the problem, give the manufacturer a call.

 Posted: 8/7/2011 

I replaced the capacitor on my motor and it operated great for about 45 days, then started to operate with some delay, then stopped working (again) all together. What could be causing this repeat of the capacitor failure?

 Posted: 6/17/2011 

I have an AO Smith pool pump motor that has two capacitors. Your article states they are for start and run but does not distinguish which is which. The shaft on my motor is free. When I try to start it there is a loud hum but if I give the shaft a slight boost by pushing the governor with a screwdriver it takes off and runs normally. Which is the start capacitor that is likely at fault?

Anonymous  Posted: 2/19/2011 

Great guide - but really hard to get replacement capacitors! My pool shop want to charge me 60 dollars for sending the pump away, even though I am pretty sure this is all it is!! I've taken the capacitor housing off - it was inundated with water, and the wires rusted in place, which is why its probably gone bad! A new one should only be about 20-40 dollars, and I can do it myself with your guide, at least give it a shot! Only need to find out where to get an ICAR Ecofill 450 VAC (MLR25PRL) from!.