Freezer displays E1 and interior temperature rises above setpoint; compressor may not start or runs briefly then stops.

Safety first: Unplug the freezer from the mains before removing any panels or touching wiring. Use insulated tools and avoid working on a wet floor.

Step-by-step checks:

• 1. Power reset: Disconnect power for 5–10 minutes, then reconnect. If E1 clears temporarily and returns, continue with diagnostics.
• 2. Locate the cabinet NTC sensor: On most Hansa freezers, the cabinet sensor is clipped behind the inner liner, often near the top or side wall. Access may require removing the interior plastic cover or light housing.
• 3. Inspect wiring and connector: Check the sensor leads from the liner to the main control board (usually in the rear or top control housing). Look for pinched, cut, or chewed wires and loose or corroded connectors. Reseat the plug firmly.
• 4. Test sensor resistance: With the unit unplugged, disconnect the NTC from the board. Measure resistance with a multimeter at room temperature (around 20–25°C). Typical NTC values are in the 5–20 kΩ range (consult Hansa service data if available). An open circuit (OL) or near 0 Ω indicates a failed sensor.
• 5. Compare resistance vs. temperature: Place the sensor tip in a cup of ice water (about 0–2°C) and re-measure. The resistance should change significantly from the room-temperature reading. If it does not change or is unstable, replace the sensor.
• 6. Check control board input: If the sensor tests good, inspect the main control board for burnt components or damaged tracks at the sensor input. If wiring and sensor are good but E1 persists, the board is likely faulty and should be replaced.

When to call a technician: If you are not comfortable using a multimeter or accessing the control board, or if the board appears damaged, contact an authorized Hansa service center.