Pump hums but will not start; may trip breaker after a few seconds (especially on single-speed SuperFlo models).

Safety first: Turn off power at the breaker and verify with a meter. Capacitors can hold a charge; discharge them safely before handling.

• 1. Check for mechanical binding: Remove the pump lid and basket. Reach the motor shaft at the rear or through the pump housing and attempt to rotate it by hand. If it is stuck, inspect the impeller for debris by separating the motor from the pump housing.
• 2. Inspect and test the start capacitor (if equipped): On non‑VS SuperFlo motors, remove the capacitor cover on top or side of the motor. Visually inspect for bulging, leaking, or burnt smell. Use a capacitance meter to test value against the rating. Replace if out of tolerance.
• 3. Verify supply voltage: Use a multimeter to ensure the motor is receiving the correct voltage under load. Low voltage can prevent starting.
• 4. Reassemble and test: After clearing debris and replacing a faulty capacitor, restore power and test. If the motor still only hums, the windings or bearings may be damaged and the motor should be replaced.