Freezer shows E4 and may not defrost, causing heavy ice on the evaporator

Safety first: Unplug the freezer. The defrost heater operates at mains voltage; do not test live unless you are qualified.

Steps:

• Manual defrost first: Fully defrost the unit for 24 hours to restore airflow temporarily.
• Access evaporator area: Remove the internal rear panel in the freezer to expose the evaporator and defrost heater assembly.
• Visual check: Look for burnt or broken heater elements and any melted connectors.
• Continuity test (for competent DIYers with a multimeter):
  • Disconnect heater terminals.
  • Measure resistance across the heater; an open circuit indicates a failed heater.
  • Check the defrost thermostat/thermal fuse (if fitted) for continuity when cold.
• Replace faulty parts: Install a genuine Beko defrost heater and/or defrost thermostat as required, ensuring correct positioning against the evaporator.
• If heater and thermostat test good, the main control board defrost relay or triac may be faulty and should be diagnosed by a professional.