H1 code, high temperature alarm active, food starting to thaw.

Safety: No internal electrical work is required for basic checks, but unplug the freezer before removing any panels.

• Check door closure: Ensure the door closes fully and the gasket seals all around. Remove any items preventing closure.
• Allow recovery time: If you recently loaded a large quantity of unfrozen food, allow 24 hours for the freezer to pull down to temperature. Use the fast-freeze function if available.
• Listen for fan and compressor: Confirm that the compressor is running and that you can hear the internal fan when the door switch is held closed.
• Inspect for ice build-up: If airflow seems weak, check for heavy frost on the internal rear panel. If present, defrost the unit fully and check the defrost system.
• Monitor temperature: Use a thermometer to verify actual temperature. If the freezer cannot reach -18 °C after 24 hours of continuous running, further diagnosis of sensors, fan, and sealed system is required.

Note: H1 is often a symptom rather than a specific component failure. If basic checks do not resolve it, follow the relevant sensor, fan, and defrost fault procedures or contact a technician.