Washer-dryer combo shows E5 and stops heating water during wash

Safety first: Unplug the unit and allow time for internal components to cool before touching the heater area.

• Confirm symptom: Run a hot wash cycle and check if the glass door and drain hose remain cold after 15–20 minutes.
• Access heater terminals: Remove the rear panel to locate the Roborock tub heater at the bottom of the outer tub. Inspect wiring connectors for burning or looseness.
• Check resistance: With a multimeter, measure resistance across the heater terminals (with wires disconnected). A typical value is 20–30 Ω; infinite or 0 Ω indicates a bad heater.
• Inspect NTC sensor: Locate the Roborock NTC sensor near the heater or in the tub wall. Check its connector and wiring. Measure resistance at room temperature and compare to service specs if available.
• If heater or NTC is faulty: Replace the Roborock tub heating element or NTC sensor as needed. If both test good, the main control board heater relay may be defective and should be replaced by a professional.