Dehumidifier displays E3 and stops dehumidifying

Safety: Turn the dehumidifier off and unplug it before removing any panels.

What E3 usually means on BONECO dehumidifiers: The control board is receiving an invalid reading from the evaporator temperature sensor (defrost sensor) or the ambient temperature is outside the operating range.

• Check ambient conditions: Ensure the room temperature is within the unit’s specified range (typically around 5–35 °C). If the room is too cold, move the unit to a warmer area and restart.
• Access the evaporator sensor: Remove the front or side cover to expose the evaporator coil (the cold, finned coil). The defrost sensor is usually clipped to the coil with a metal or plastic clip and connected by two wires to the PCB.
• Inspect sensor placement: Confirm the sensor is firmly attached to the coil surface. If it has fallen off, re-clip it securely to the coil in its original position.
• Check wiring: Follow the sensor wires back to the main board. Look for cuts, pinches, or loose connectors. Reseat the connector on the PCB.
• Resistance test (optional): With the unit unplugged and the sensor disconnected, measure resistance with a multimeter. Compare to service data if available; a reading of open circuit or 0 Ω indicates a bad sensor.
• Replace the sensor if faulty: Install a new evaporator temperature / defrost NTC sensor compatible with your BONECO dehumidifier. Clip it to the same coil location and route the cable away from the fan and sharp edges.
• If E3 remains after sensor replacement: The main control board may be defective. Professional diagnosis and main PCB replacement is recommended.