AO Smith variable-speed pool pump runs briefly, then stops and displays “ERR5”.

Safety First: Turn OFF power before cleaning or touching the motor housing.

• Inspect ventilation: Check that the motor cooling vents and fan shroud are not blocked by leaves, dirt, or insulation. Clean with a soft brush or compressed air.
• Improve airflow: Ensure there is adequate clearance around the pump (at least several inches on all sides) and that it is not enclosed in a sealed box. Provide louvers or vents if in a shed.
• Shade the pump: If the pump is in direct sun, consider adding a shade cover that does not restrict airflow to reduce heat load.
• Check motor temperature: After running, carefully feel the motor housing (it will be hot but should not be too hot to touch briefly). Excessive heat may indicate bearing drag.
• Run at lower speed: Program the pump to run at a lower RPM for longer periods instead of high speed continuously. This reduces heat generation.
• Service bearings or replace motor: If overheating continues and the shaft feels rough or noisy when spun by hand, the motor bearings may need replacement or the entire motor assembly may need to be replaced.