Pool Pump Motor Capacitors
A capacitor is like the battery in your car, but for your pool pump motor. A pool pump start capacitor provides the extra energy needed while starting, to reach 3450 rpm quickly.
Pool pump start capacitors are available as small black cylinders, 2-3” long which are usually located in the rear of the motor, at 9 o’clock. These are known as Start Capacitors, and are rated for 115VAC, available in different MFD sizes for pumps of varying horsepower and service factors.
Pool pump run capacitors are also available as larger silver cylinders, 3-4” long and much thicker than the black cylinder capacitors. These are usually located on top of the pump motor, in the “hump”, and are known as Run Capacitors, and are rated for 370VAC, in different MFD sizes for pumps of varying size.
Pool Pump Capacitor Replacement Tips:
- Replace your Capacitor when the shaft or impeller spins freely, and when powering the motor, you hear a 'buzz' or a 'hum' from the motor, which may trip the breaker.
- Start Capacitors have a limited service life of approximately 5000 starts of the pool pump motor. Run Capacitors typically last longer.
- Pool pump capacitors that have failed may be cracked, bulged or burned in appearance, and may have a burned electrical smell.
- Capacitors can be tested for “Capacitance” or available starting power, by using a multimeter set to the highest level for Ohms.
- Replace your pool pump capacitor with an exact match to the 'MFD' number on the capacitor. If unreadable, multiply motor label HP x SF x 75 to approximate.
For information on replacing pool motors, seal or capacitor, Visit our Pumps and Motors Technical Arcticle in our Pool Info Section.