Pool pump won't start (or hums without turning)

Updated : November 10, 2026 · Piscines VP

If the pump makes no sound at all, check the power: breaker, GFCI outlet, timer. If it hums without turning, cut the power right away: the cause is often the start capacitor or a seized motor (bearings, debris). Don't let it hum, the motor can burn out.

A pump that won’t start is usually one of the four problems below. Always cut the power before touching the pump.

No sound at all

Timer: is it set to the right time? Are the trippers in place?
Breaker: has it tripped? See Pump tripping the breaker.
GFCI outlet (“test/reset” button): has it tripped?
Variable-speed pump: does the display show an error code? Check the manual.

It hums but doesn’t turn

Cut the power right away. A motor that hums without turning heats up very fast.

Common causes:

weak or failed start capacitor;
seized motor: stuck bearings (often after a shaft-seal leak), see Worn bearings;
impeller jammed by debris.

It starts, then stops

Often the thermal protection. See Overheating pump.

In spring

A pump that spent the winter somewhere damp can have rusty bearings or a stuck motor. Test it for a few seconds before reinstalling it, and see Reinstalling your pump in spring.

Piscines VP repairs pump motors in Laval and the Basses-Laurentides, Quebec.

Frequently asked questions

Can I replace the capacitor myself?

A capacitor holds an electrical charge even when the pump is unplugged. Replacement should be done by a qualified person, with the right part.

My pump starts if I spin the shaft by hand, what does that mean?

It's a classic sign of a weak capacitor or a motor that's straining. Have it checked: forcing a start every time wears out the motor.

Not sure of the cause? Take the 2-question diagnosis →

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