Display shows E04 and unit shuts down; may occur during very cold or very hot ambient conditions.

Safety first: Disconnect power before removing panels or touching internal components.

• Check for ice on coil: Inspect the evaporator coil (the large finned coil around the unit). If it is covered in ice, turn the unit off and allow it to defrost completely. Ensure fan operation and clear airflow.
• Inspect sensor connection: Locate the evaporator temperature sensor clipped to the coil. Make sure it is firmly attached and the plug is fully seated on the main control board.
• Check wiring: Look for pinched, cut, or corroded sensor wires. Repair or replace damaged wiring.
• Reset unit: After defrosting and checking connections, restore power and clear the E04 code via the control panel.
• Replace sensor if needed: If E04 persists and wiring is intact, the sensor itself is likely faulty and should be replaced with a compatible SPRSUN evaporator temperature sensor.