Indoor unit shows E4 and stops; may occur during heating or cooling, often after running for some time.

Safety: The discharge pipe can be extremely hot during operation. Ensure power is off and the unit has cooled before touching any piping.

• 1. Access outdoor unit: Turn off power, remove the service panel, and locate the compressor and discharge line (small copper pipe leaving the compressor).
• 2. Find discharge sensor: Look for a clip-on or strapped sensor on the hot gas line near the compressor, with two wires going to the PCB.
• 3. Check attachment: Ensure the sensor is firmly clamped to the pipe and insulated if originally wrapped. Re-secure with metal clip or high-temp tape as needed.
• 4. Inspect wiring: Look for melted insulation, chafing, or loose connectors. Repair or replace damaged wiring.
• 5. Test sensor: With the sensor disconnected and cooled to ambient, measure resistance and compare to expected NTC values. Replace if open/shorted.
• 6. Replace sensor if needed: Install a new Beko discharge pipe temperature sensor and secure it firmly to the pipe.
• 7. If E4 remains: The outdoor PCB may misread the sensor and require replacement by a professional.