Display shows H1 or HI; audible alarm sounds and interior temperature is too warm.

Safety: No immediate electrical hazard, but avoid leaving food in unsafe temperatures.

Steps:

• Check door seal: Ensure the door is fully closing and the gasket is not obstructed by packages or frost. Clean gasket with warm soapy water and dry.
• Allow recovery: If you recently loaded warm food or had a power outage, allow 12–24 hours for the freezer to pull down to set temperature. Keep the door closed as much as possible.
• Verify temperature: Place an appliance thermometer inside and compare to the display. If the display shows H1 but the actual temperature is normal, suspect a sensor or control issue.
• Check for running compressor and fans: Listen for compressor and fan operation. If they are not running, investigate compressor start components, fans, or control board.
• Inspect condenser: Clean dust from the condenser coils and ensure adequate airflow around the unit.
• Sensor check: If the unit cools but still shows H1, test and replace the cabinet temperature sensor or main control board as needed.

Food safety: Discard perishable items that have been above 0°F (-18°C) for extended periods.