Dehumidifier stops and shows E4 on the display

Safety: Unplug the unit before removing covers. Do not attempt to open the sealed refrigeration system; that requires EPA-certified service.

Steps:

• Check ambient conditions: TaoTronics dehumidifiers are typically designed to operate above about 41°F (5°C). If the room is too cold, ice can form and trigger E4. Move the unit to a warmer room and allow it to thaw completely for several hours.
• Inspect airflow: Remove and clean the air filter. Check that the intake and exhaust grilles are not blocked by walls, curtains, or furniture. Maintain at least 12–16 inches of clearance around the unit.
• Check for ice buildup: With the cover removed, inspect the evaporator coil. If it is heavily iced over, unplug the unit and let it defrost fully. After thawing, restart and observe. Persistent rapid icing may indicate low refrigerant or poor airflow.
• Verify fan operation: Turn the unit on and confirm the cross-flow or axial fan motor runs at normal speed. A slow or non-running fan will cause coil freeze-up and E4.
• Sensor check: Ensure the evaporator NTC sensor is firmly attached to the coil and wiring is intact (see E2 procedure). A misreading sensor can falsely trigger E4.
• If airflow and sensor are OK but E4 persists: The issue may be a sealed system problem (low refrigerant, restriction, or compressor issue) or a defective main control PCB. These repairs require a professional technician with refrigeration tools.