Microwave shows H1 or HI and stops; exterior of unit may feel very hot.

Safety: Unplug the microwave and allow it to cool completely before further use.

Steps:

• 1. Improve ventilation: Ensure at least 10 cm clearance on sides and rear, and that top vents are not blocked by cabinets or objects.
• 2. Clean vents: Use a vacuum and soft brush to remove dust from intake and exhaust grilles.
• 3. Check fan operation: After cooling, run a short cook cycle and listen for the internal fan. If you do not hear it, the fan motor or its wiring may be faulty (see E4).
• 4. Reduce duty cycle: Avoid running multiple long, high-power cycles back-to-back. Allow rest periods between heavy uses.
• 5. Sensor check: If H1 appears quickly even with good ventilation and a working fan, the overheat sensor or thermostat may be faulty and should be tested and replaced by a technician.