Pump stops shortly after starting, controller displays E02 and will not restart until cooled.

Safety: Isolate power at the breaker and pump isolator before inspection.

• Check ventilation: Ensure the Onga pump motor cooling fins and rear fan cover are free of dust, cobwebs, and leaves. Clean with a soft brush and low-pressure air.
• Improve airflow: If the pump is in a tight enclosure, open vents or doors while running. Ensure at least several centimeters of clearance around the motor for airflow.
• Check supply voltage: Use a multimeter (if competent) to verify voltage at the pump terminals is within the rated range on the Onga motor nameplate. Persistent low or high voltage requires an electrician.
• Spin test: With power OFF, rotate the motor shaft/fan by hand. If it feels rough or stiff, the bearings are likely failing and causing overheating.
• Duty cycle: Confirm the pump is not being run dry or with closed valves, which can cause overheating. Ensure suction and return valves are open and water is flowing.

If E02 persists after cleaning and ensuring proper flow and voltage, the internal thermal protector or motor windings may be damaged; replace the motor assembly.