Display shows H1 or HI and an alarm sounds; interior temperature is too high.

Safety: No internal electrical work is required for basic checks, but unplug the unit if you remove panels.

Steps to respond to H1/HI:

• Check door closure: Ensure the freezer door or lid is fully closed and the gasket is not obstructed by food packages or ice.
• Inspect door gasket: Run your hand around the gasket to feel for cold air leaks. Look for tears, gaps, or warped sections.
• Reduce warm load: If you recently added a large quantity of unfrozen food, allow 12–24 hours for temperature to recover. Avoid overpacking against the air vents.
• Verify compressor operation: Listen at the back for the compressor running (a low humming sound) and check if the condenser coils are warm after 15–20 minutes of operation.
• Check interior fan (upright models): Open the door briefly and listen for the evaporator fan. It should run when the compressor is on and the door switch is closed.
• Clear vents: Make sure interior air vents are not blocked by baskets or food, which can cause warm spots and alarms.
• Reset alarm: Most Costway freezers allow you to silence the alarm by pressing the alarm or set button. The code will clear automatically once temperature returns to normal.

Call a technician if: The compressor is not running, or the unit cannot reach freezing temperature after 24 hours with a light load and good door seal. This may indicate a sealed system or compressor fault.