Washer-dryer shows E20 and may not heat during drying; often associated with overheating protection.

Safety first: Unplug the appliance and allow it to cool fully before working on the dryer system.

Step-by-step checks:

• 1. Thorough cleaning: Remove and clean all accessible lint filters and the condenser unit. Vacuum lint from around the dryer heater housing and ducts.
• 2. Check air intake and exhaust: Ensure the front and rear vents are not blocked by dust or objects. The machine needs adequate airflow around it.
• 3. Test high-limit thermostat: Locate the high-limit thermostat on the dryer heater housing. With the machine unplugged, test for continuity. Replace if open circuit and non-resettable.
• 4. Inspect dryer NTC: Test the dryer NTC sensor resistance at room temperature and replace if readings are out of specification.
• 5. Fan operation: Confirm that the dryer fan motor runs during drying. If not, test and replace the fan motor as needed.
• 6. PCB control: If all components are good and airflow is clear but E20 persists, the PCB may be incorrectly detecting overheat and require replacement.