Washer-dryer does not heat water; cycles run cold and may extend in time with E05 displayed

Safety first: Unplug the appliance and allow it to cool before accessing internal components.

• 1. Confirm symptom: Run a hot wash program and check if the door glass becomes warm after 20–30 minutes. If not, heating is likely not occurring.
• 2. Access heater terminals: Remove the rear panel (or front lower panel on some models) to locate the heating element mounted in the bottom of the tub.
• 3. Inspect wiring: Check for burnt connectors or loose spade terminals on the heater and NTC sensor. Reseat any loose connections.
• 4. Test heater resistance: Using a multimeter, measure resistance across the heater terminals. A typical Bosch heater is around 20–30 Ω. Infinite resistance indicates an open heater that must be replaced.
• 5. Test NTC sensor: Measure resistance of the NTC at room temperature (usually 4–6 kΩ). If reading is open, shorted, or does not change with temperature, replace the NTC sensor.
• 6. Replace faulty parts: Remove the heater retaining nut, gently pry out the element, and install a new Bosch tub heating element and/or NTC as required, ensuring the seal is properly seated to prevent leaks.
• 7. If E05 persists: The main control board heater relay or triac may be defective. This requires professional electronic diagnosis and repair.