Microwave displays H0 or HO and will not start, often after heavy use.

Safety: Unplug the microwave and allow it to cool for at least 30 minutes.

• Step 1 – Allow full cooling: Leave the door open and let the unit cool completely. After cooling, plug back in and check if the H0 code clears.
• Step 2 – Check ventilation: Ensure there is adequate space around the microwave as specified in the Swan manual. Clear any obstructions from intake and exhaust vents.
• Step 3 – Inspect cooling fan: Remove the outer cabinet and verify that the cooling fan spins freely and is not obstructed by dust or debris. Replace the fan motor if it does not run during operation.
• Step 4 – Clean filters (if built-in): For built-in Swan microwaves with grease or charcoal filters, remove and clean/replace them to improve airflow.

If H0 returns frequently despite good ventilation and a working fan, an overheat sensor or control PCB fault may be present and should be checked by a technician.