Dehumidifier displays E4 and shuts down; may occur after long runtime

Safety: Unplug the unit. Do not attempt to open the sealed refrigeration system yourself; that requires a licensed technician.

User-level checks:

• Remove and thoroughly clean the air filter. Rinse with warm water, dry completely, and reinstall.
• Inspect the evaporator coil through the grille. If it is heavily iced, leave the unit unplugged with panels open for several hours to fully defrost.
• Ensure there is at least 30 cm clearance around the unit for proper airflow. Do not operate it in very low ambient temperatures (below the specified range in the manual).

Technical checks (for experienced DIYers):

• Access the evaporator defrost sensor (if separate from the main evaporator NTC). Check that it is firmly attached to the coil and that wiring is intact.
• Test the sensor resistance and compare with service data. Replace with a Dimplex defrost/coil sensor if out of range.
• Inspect the fan motor and fan wheel for dust buildup or obstruction that could reduce airflow.

When to call a technician: If E4 persists after cleaning filters, defrosting, and verifying sensors, the issue may be low refrigerant, a blocked capillary, or a failing compressor. These require professional refrigeration service.