Indoor unit displays F1; unit may run briefly then stop; often related to outdoor coil temperature sensing.

Safety: Isolate power at the breaker. Outdoor coils have sharp fins; wear gloves.

Steps:

• 1. Access outdoor coil: Remove the outdoor unit side panel to expose the condenser coil and sensor wiring.
• 2. Locate coil sensor: Find the NTC sensor clipped to the condenser coil tubing, usually near the middle or outlet side, with two wires going to the PCB.
• 3. Check attachment: Ensure the sensor is firmly clipped to the copper tube. Reattach if loose or hanging.
• 4. Inspect wiring: Follow the sensor wires to the outdoor PCB. Look for cuts, abrasions, or UV damage. Reseat the connector.
• 5. Measure resistance: With power OFF, disconnect the sensor and measure resistance at ambient temperature. Compare to typical NTC values or to another similar sensor in the system. Replace if open/shorted.
• 6. Replace sensor: Install a new Airwell outdoor coil sensor of the same type. Clip it securely and route wires away from hot or moving parts.
• 7. PCB check: If the sensor is good but F1 persists, the outdoor PCB sensor circuit may be faulty and require replacement.