How To Tell If a Pool Pump Capacitor Is Bad (Quickly & Easily!)

Nick Durante
by Nick Durante

Pool pumps are a necessary part of swimming pool health, and they help sanitize the water. However, they can run into trouble and fail to operate properly if the capacitor is outdated or damaged. So, how can you tell if a pool pump capacitor is bad?

Test your pool pump capacitor with a multimeter to find out if it is bad. Remove the cover and connect the nodes on your multimeter to each terminal to diagnose your capacitor. Pool pump capacitors last for 10-15 years, and you can it is bad if it overheats or buzzes during operation.

Some signs of a bad capacitor are similar to failing pool pump motor symptoms. That is why it is important to test your capacitor with a multimeter. Follow along as we dive into what you can do to find out if your pool pump capacitor is bad.

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How Do You Test a Capacitor On a Pool Pump?

You can test your pool pump capacitor with a tool called a multimeter. Consider the age of your pool pump capacitor as well because they go bad over time. Your pool pump capacitor may be bad if it is between 10 and 15 years old, depending on how much you’ve used it.

Pool pump capacitors generally wear out after you start it 5,000 times. However, pool pump capacitors can run into problems long before then. Let’s take a look at what you can do to test your pool pump capacitor and see if it still works.

How To Test a Pool Pump Capacitor With a Multimeter

Purchase a multimeter so that you can find out if there is still life in your pool pump capacitor. You can find multimeters are home improvement and hardware stores for $10-$50. Turn your pool pump’s power off from the electrical box before you begin and test your capacitor.

Pool pump capacitors can even retain energy after you turn them off. That is why you need to wear gloves and protective face and ear gear. Find out what size breaker you need for a pool pump.

1. Remove Cover

Look for the round cover over your pool pump motor. You can usually find the cover at the back of the motor. Open the cover and find the screws that hold the cover in place.

There are usually 2 screws, and you can remove them with a screwdriver. You should see the capacitor once the cover is out of the way. Pool pump capacitors typically measure 3”-4” long and are shaped like a cylinder.

2. Drain Power

Pool pump capacitors can store energy, which is efficient, but can be dangerous. Your capacitor still has energy even you turn off the power, so you need to safely drain it. Wear gloves and eye protection because capacitors can burst if they short out.

Connect both of the capacitors leads with an insulated screwdriver to release the energy. You will hear a popping sound as the energy leaves the pool pump capacitor, and that is perfectly normal.

3. Remove the Lead Wires

Take a pair of needle-nose pliers and grab the two lead wires that you used to drain the capacitor one at a time. Carefully pull each lead wire away from the terminal with your pliers so that you can safely test the capacitor. Keep track of where you place the lead wires after you disconnect them so that you can reconnect them later.

4. Use Multimeter

Check to make sure that your capacitor is rated at no more than 150 microfarads. If it is, you can take your multimeter and program it to ohms to 1k to get a reading from your pool pump capacitor. Make sure to use the lowest ohm setting that your multimeter has.

Separate the two probes on your multimeter and attach them to each terminal on your capacitor. You can tell that your capacitor is bad if the needle never moves from the zero position. Healthy capacitors usually slowly climb from zero and eventually speed up to reach the maximum number.

It is easier to read digital multimeters because there isn’t always a needle, and instead it displays numbers. Some analog multimeters don’t have numbers, and you’ll have to watch the needle. The needle should move to the right and bob back to the left if your capacitor is healthy.

Signs of a Bad Pool Pump Capacitor

It can be difficult to tell if your pool pump capacitor is bad when you experience motor problems. Wiring and motor problems are easy to mistake for an outdated pool pump capacitor. Let’s take a look at the most common signs that your pool pump capacitor is broken.

Slow Speed

Capacitors directly affect your pool pump motor’s performance. A slow-moving pool pump motor is a telltale sign that your capacitor is outdated or broken. Sometimes, a bad capacitor can also make your motor get stuck at a high speed.

Test your capacitor if that is the only problem that you have with your pool pump. It may be a problem with the wiring or motor itself, so your capacitor may not be the problem.


The easiest way to tell that your pool pump capacitor is bad is if it buzzes during operation. Your pool pump motor needs your capacitor to run smoothly, and it will buzz if the capacitor isn’t working. However, buzzing sounds can also indicate a problem with the motor shaft.

Inspect the motor shaft to look for damage or debris that can clog it. You can tell that the capacitor is the problem if the shaft won’t spin automatically, but it will manually.

Running Hot

Your pool pump capacitor is likely damaged or outdated if your motor is running hot. Pool pump motors often are hot when they run, but they rarely overheat unless there is a problem. Most pool pump motors automatically shut off when they overheat.

You will notice right away that it shuts off if you are outside, or if you notice later that the pump didn’t do its job.

Related Questions

How long should a pool capacitor last?

The average pool capacitator lasts 10 years, but it can last as long as 15 years. Your pool capacitor can go bad before then if you start it over 5,000 in under 10 years. Pool capacitors are built to last for 5,000 starts, so it depends on how often you run your pump.

How long should a pool pump run each day?

You should run your pool pump for up to 8 hours each day. It is okay to run your pool pump for longer if you need to improve the water circulation. The average pool pump can circulate all of the water within 8-10 hours, if not sooner.

What do pool pumps do?

Pool pumps circulate water and chemicals in the pool to keep it clean and fight germs. The pump circulates water between the heater, filter, and skimmer to evenly sanitize your pool. Circulation helps maintain balanced chlorine levels and alkalinity in your pool.

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Summing It Up

You can tell that your pool pump capacitor is bad if it doesn’t read on a multimeter. Other signs include buzzing during operation, overheating, and problems with motor speed. Test your capacitor with a multimeter to find out if that is the cause of the problem, or if it is the motor itself.

Digital multimeters are easier to read, and you can watch the number come up from 0. Your capacitor is bad if it stays at zero during the reading. If your capacitor is older than 10-15 years, it is likely out of date and you need to replace it.

Nick Durante
Nick Durante

Nick Durante is a professional writer with a primary focus on home improvement. When he is not writing about home improvement or taking on projects around the house, he likes to read and create art. He is always looking towards the newest trends in home improvement.

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