Digital controller shows E03 and pump does not run, often after a power cut or wiring work.

Safety: Only a qualified electrician or pool technician should work inside the control panel. Isolate and lock off the supply.

• Check incoming phases: Using a multimeter, verify all three phases (L1, L2, L3) are present at the Certikin controller or inverter terminals and are within the specified voltage range.
• Inspect terminals: Tighten all terminal screws on the pump contactor, overload, and controller. Look for signs of overheating or discoloration on the wiring.
• Check fuses and breakers: Replace any blown fuses on individual phases and reset tripped MCBs. Confirm correct fuse ratings per the Certikin pump data plate.
• Verify motor wiring: Ensure the motor is wired correctly (star/delta as specified). Incorrect configuration can be detected as phase fault by the controller.

After correcting any supply issues, clear the E03 fault on the controller (usually by pressing STOP/RESET) and attempt a restart. If E03 remains, the inverter or controller may be faulty and require replacement.