How To Tell If Pool Pump Capacitor Is Bad

Knowing how to check your pool pump condenser can save you time and money when the pump motor fails. With each day that the pump fails, the potential for a lengthy and costly cleanup increases. Pump motor troubleshooting should begin with checking the capacitor(s).

What is a capacitor?

Contents

The basic definition of a capacitor is a device used to store electrical charge. Most pool pump motors use a starting capacitor and/or a run capacitor. Both look similar to one large battery. The starting capacitor is usually located at the rear of the motor and the running capacitor is located at the top of the motor.

Symptoms of a bad capacitor

Roaring. Is your pool pump motor humming but not turning on? Most pool motors require extra torque for the motor to accelerate. A damaged capacitor will prevent the motor from spinning. Another cause of noise could be a stuck motor shaft. If you can turn the motor shaft by hand, the capacitor could be the cause of the noise. If the shaft does not rotate by hand, you should replace the complete bearing or motor. Read more: How to use root tabs to fertilize aquatic plants Pool motors typically run on the hot side. However, the motor will turn itself off if it runs too hot. A faulty capacitor can cause the motor to run at a higher amperage. Higher amps mean more power, and more power means more heat. Other symptoms of an overheating pool motor are oversized propellers, bad windings, or high voltages. One speed working on two speed motor. There are several reasons why two-speed pool pump motors run only at high or low speeds. As you might have guessed, capacitor run is a frequent fault. If it’s not the capacitor, it’s most likely a bad phase coil and the motor needs to be replaced. Read more: how to make baby slippers | Top Q&ARead more: how to make baby slippers | Top Q&A

Check the capacitor with a multimeter

Remove the cap on the back of the motor or on top of the motor to reveal the capacitor.

The capacitor will store an electrical charge. It will need to be short-circuited by placing an insulated screwdriver across the leads of the capacitor. CAREFUL: Capacitors have been known to explode when short-circuited. For this reason, wear eye protection and place a cloth over the capacitor before shorting the capacitor.

Remove the wires leading to the pool pump condenser. Note the position of the leads so that you can restore them to the correct position when you reconnect them.

Set the multimeter on ohms to 1K.

Slide a piece of heavy paper between the points on the switch.

Attach a probe to each terminal. On an analog clock, the right hand moves quickly to the right and then slowly to the left. If a digital meter is used, the readings should start low and rapidly increase to the maximum value. If the needle or number starts at 0 and does not move, the capacitor is damaged and therefore needs to be replaced.

Replacement

Replacement capacitors must have the same MFD or UF rating as the original. If the same voltage rating is not available, the next higher voltage may be acceptable. For example, if a 370 volt unit is not available, use the next rating of 440 volts.