Display shows E4; unit may start but quickly stops, often with no ice forming on the evaporator.

Safety first: Disconnect power before removing internal covers or touching the evaporator assembly.

Steps to address E4:

• 1. Visual inspection: Open the lid and locate the evaporator (cold metal fingers or plate where ice forms). Look for a small sensor clipped or taped to the evaporator surface.
• 2. Check sensor placement: Ensure the sensor is firmly attached to the evaporator and has not fallen off. If it is loose, reattach it using thermal tape or the original clip so it makes good contact with the metal.
• 3. Inspect wiring: Trace the sensor wires back to the main PCB. Look for cuts, pinches, or melted insulation. Reseat the connector on the board.
• 4. Test the sensor: With a multimeter, measure resistance at room temperature and compare to the expected NTC value (consult the HOMCOM service data if available). An open or shorted reading indicates a bad sensor.
• 5. Replace the evaporator sensor: If faulty, install a compatible HOMCOM evaporator NTC sensor. Route the wires away from moving parts and secure them with cable ties.
• 6. Reassemble and test: Refit any covers, restore power, and run a full cycle. Confirm that ice begins to form and E4 does not reappear.

Note: If the sensor is good but E4 persists, the main control board may need replacement by a qualified technician.