Dehumidifier shows E4 and shuts down shortly after starting.

Safety: Unplug the unit before inspection. Do not attempt to open the sealed refrigeration system (compressor, coils, refrigerant lines).

Steps to troubleshoot E4:

• Check ambient conditions: Ensure the unit is used within the specified temperature range (typically 5–32°C / 41–90°F). Very low room temperatures can cause coil freeze and E4 errors.
• Clean the air filter: Remove the intake filter and wash it with mild soap and water. Let it dry completely before reinstalling. Blocked filters reduce airflow and can trigger E4.
• Inspect airflow: Make sure there is at least 20–30 cm (8–12 in) clearance around the air intake and exhaust. Remove any obstructions.
• Check the evaporator coil: With the unit unplugged, remove the front panel and visually inspect the evaporator coil. If it is heavily iced over, allow it to fully defrost (leave unplugged for several hours) and then restart.
• Verify coil sensor (if E2 not present): Ensure the evaporator temperature sensor is firmly attached to the coil and wiring is intact (see E2 procedure). A misreading sensor can cause E4.
• Test after cleaning and defrosting: Reassemble, plug in, and run the unit. If E4 returns quickly and the coil does not get cold or gets only partially cold, there may be a sealed system problem (refrigerant leak or restriction) or a control board fault.
• Do not attempt sealed system repair: Refrigerant work requires specialized tools and certification. Contact a professional technician or Pro Breeze support if E4 persists after airflow and sensor checks.