Pump hums but does not start; may trip breaker after a few seconds.

Safety first: Unplug the pump and allow any moving parts to stop completely.

• Check impeller movement: Remove the pump lid and basket. Try to rotate the impeller by hand. If it is stuck, clear debris or consider bearing replacement.
• Listen for grinding: If the impeller is hard to turn or makes grinding noises, the bearings may be seized, requiring motor replacement.
• Avoid repeated restarts: Do not repeatedly reset breakers or try to start a locked motor; this can cause further damage.
• Capacitor/motor service: If the impeller spins freely but the pump only hums, the start capacitor or motor windings are likely faulty and should be checked by a technician.