A pump that will not work is frustrating but rarely mysterious. Split the problem into power, the motor itself, and water flow, and the cause almost always lands in one of those three.
What you are seeing
The pump will not turn on, hums without spinning, trips the breaker, or runs but moves little or no water. You may notice heat, noise, or no sound at all.
Possible causes
- No power reaching the motor A tripped breaker, failed timer, loose wire, or bad switch stops the motor before anything else can happen.
- Failed start capacitor A pump that hums but will not spin often has a dead start capacitor, a common and inexpensive failure.
- Seized or clogged impeller Debris jamming the impeller, or a seized bearing, stops the motor from turning freely.
- Lost prime or air lock If the pump runs but moves no water, it may be pulling air rather than water on the suction side.
How to check
- Confirm the breaker is on and the timer is calling for the pump to run.
- Listen: a hum with no spin points at the capacitor or a jammed impeller.
- Cut power, then check whether the motor shaft turns freely by hand.
- Check the pump basket and skimmer for debris, and confirm water is above the skimmer.
How to fix it
- Restore power Reset the breaker, check the timer, and confirm wiring connections are sound. Call an electrician for anything beyond a reset.
- Replace a failed capacitor If the pump hums but will not start, a replacement start capacitor matched to the motor usually brings it back. Discharge it safely first or have a pro handle it.
- Clear the impeller With power off, remove debris packed into the impeller so it spins freely again.
- Re-prime the pump If it runs but moves no water, seal the suction side, top up the water level, and re-prime so it stops drawing air.
How to prevent it
- Keep baskets clear so debris never reaches the impeller.
- Protect the equipment pad from water intrusion at the electrical connections.
- Address unusual noise or heat early, before a bearing or capacitor fails outright.