Indoor unit shows F1; unit may run but with poor temperature control or may shut down intermittently.

Safety: Turn off power before opening the indoor unit.

• Step 1 – Locate room sensor: The ambient sensor is usually near the air intake grille on the indoor unit, often behind the front panel. It is a small probe or thermistor with two wires.
• Step 2 – Check mounting: Ensure the sensor is positioned in the return air stream and not touching cold coil surfaces.
• Step 3 – Inspect wiring: Follow the sensor wires to the PCB. Check for damage and reseat the connector.
• Step 4 – Replace sensor: If the sensor is cracked or F1 persists, replace it with a Senville-compatible room temperature sensor.
• Step 5 – PCB check: If a new sensor does not clear F1, the indoor PCB may be defective and require replacement.