Freezer shows E3 and may not defrost properly, leading to heavy ice build-up on the evaporator and poor cooling.

Safety first: Unplug the freezer. Ice and water around electrical parts are hazardous—keep the area dry while working.

Steps to troubleshoot:

• 1. Defrost the unit: Leave the door open and place towels to catch meltwater, or use a fan to speed up defrosting. Do not use sharp tools or open flames to remove ice.
• 2. Remove evaporator cover: Once ice is melted, remove the inner rear panel to expose the evaporator and defrost components.
• 3. Identify defrost sensor/thermal fuse: On Bomann freezers, this is typically a small cylindrical or flat sensor clipped to the evaporator tubing, sometimes in series with a thermal fuse wrapped in insulation.
• 4. Test continuity: Disconnect the sensor/fuse assembly and check continuity with a multimeter. An open reading on a thermal fuse or sensor that should be closed at low temperatures indicates failure.
• 5. Inspect wiring: Look for burnt insulation, brittle wires, or loose connectors. Repair any damaged sections and ensure tight connections at the main board.
• 6. Replace faulty components: Install a new Bomann-compatible defrost sensor/thermal fuse assembly. Clip it securely to the evaporator in the original position to ensure accurate temperature sensing.
• 7. Reassemble and test: Refit the evaporator cover, restore power, and monitor for recurrence of E3 and for proper automatic defrosting over the next 24–48 hours.

Warning: If you find signs of overheating or melted plastic around the defrost area, have a professional inspect the system for safety.