Summit freezer display shows H1 or "HI" and an audible alarm sounds; interior feels warm.

Safety note: This is primarily an operational/temperature alarm, not an electrical hazard, but always unplug the unit before removing panels.

Steps to respond to H1/HI:

• Check door closure: Ensure the door is fully closed and the gasket is sealing all around. Remove any items blocking the door from closing.
• Allow recovery time: If you recently loaded many unfrozen items or had the door open for an extended period, allow 12–24 hours for the temperature to recover. Avoid frequent door openings.
• Verify setpoint: Confirm that the temperature setpoint on the control is appropriate for a freezer (typically around -18°C / 0°F).
• Listen for compressor and fan: With the door closed, listen for the compressor and interior fan running. If both are off for long periods while the interior is warm, there may be a control or compressor issue.
• Check for frost pattern: If comfortable removing the interior rear panel, inspect the evaporator coil. A light, even frost pattern indicates normal operation; heavy ice or no frost at all suggests a defrost or sealed system problem.
• Inspect temperature sensor: If the interior is clearly cold but the display shows high temperature, the cabinet thermistor may be faulty. See the E1 procedure for checking and replacing the sensor.
• Silence alarm (if possible): Use the alarm mute button on the control panel to silence the beeper while troubleshooting.

When to call a technician: If the freezer does not cool despite the compressor running, or if there is no frost on the evaporator, a sealed system issue (refrigerant leak, restriction, or weak compressor) is likely and requires professional service.