Pump is humming but will not start; may trip breaker after a few seconds

Safety first: Turn off power at the breaker and verify no voltage is present before opening the motor capacitor cover.

• Check for free shaft rotation: With power OFF, remove the rear cover and try to spin the motor shaft by hand. If it is stiff or locked, investigate for impeller blockage or bearing failure.
• Inspect and test capacitor: Locate the capacitor can on the Harris motor, discharge it safely, then remove and test with a capacitance meter. Replace if out of tolerance or visibly swollen.
• Clear impeller blockage: If the shaft is hard to turn, remove the motor from the pump housing and inspect the impeller for debris. Clean and reassemble with a new shaft seal if needed.

If the motor still only hums after capacitor replacement and clearing obstructions, the windings may be damaged and the motor should be replaced.