Indoor unit displays F2; the unit may stop or run erratically.

Safety first: Turn off power at the breaker before accessing the indoor unit internals.

Steps to check:

• 1. Locate T2 sensor: Remove the front panel and filters. The T2 sensor is usually clipped directly to the evaporator coil tubing.
• 2. Check mounting: Ensure the sensor is firmly clipped to the coil and making good contact with the copper tube. Re-clip if loose.
• 3. Inspect wiring: Follow the sensor wires to the PCB. Look for cuts, pinched sections, or signs of rodent damage. Ensure the connector is fully inserted.
• 4. Replace if necessary: If the sensor appears damaged or if F2 persists, replacing the T2 sensor is usually straightforward: unplug the old sensor, remove it from the coil, clip in the new one, and reconnect.

When to call a technician: If a new sensor does not resolve F2, the indoor PCB sensor circuit may be defective and should be tested and replaced by a professional.