Digital controller shows E04 and pump will not start; sometimes accompanied by tripped GFCI or breaker.

Safety First: Turn OFF the breaker and verify power is off. Do not bypass GFCI protection.

• Inspect for moisture: Remove the motor junction box cover and the Rheem control module cover. Look for condensation, rust, or water tracks. Dry components thoroughly with a clean cloth and low‑heat air (no open flame).
• Check wiring insulation: Examine all motor leads and control wires for nicks, cracks, or melted spots where copper is exposed or touching metal. Repair with heat‑shrink or replace damaged wires.
• Test motor to ground: With a megohmmeter (insulation tester), test resistance between each motor lead and ground. Very low resistance indicates a ground fault; replace the motor.
• Inspect control module: If the Rheem control board shows corrosion or burn marks, replace the control module. Ensure all gaskets and covers are properly sealed to prevent future moisture ingress.
• Reset GFCI and test: After repairs, reset the GFCI/breaker and start the pump. If E04 or nuisance tripping persists, have a qualified technician perform advanced insulation testing.