Luxaire air conditioner displays F3; unit may short cycle or fail to maintain setpoint.

Safety: Disconnect power to the indoor unit.

• Access the coil: Remove the air handler or coil access panel to expose the Luxaire evaporator coil.
• Locate the sensor: Look for a small probe or bead thermistor clipped to the coil tubing or inserted into a well.
• Reattach or replace: If the sensor has fallen off, reclip it firmly to the coil. If the sensor is damaged or corroded, replace it with the correct Luxaire coil sensor.
• Secure wiring: Route sensor wires away from sharp metal edges and moving blower parts. Use zip ties as needed.
• Test operation: Restore power and run cooling. If F3 persists, the indoor control board may be misreading and need professional diagnosis.