Unit displays E3 and stops cooling, outdoor or rear section may shut down.

Safety first: Disconnect power. The condenser area can be hot and has sharp fins; wear gloves.

• Step 1 – Access condenser: On portable Sencor units, remove the rear panel. On split units, the condenser sensor is in the outdoor unit behind the grille.
• Step 2 – Locate sensor: Look for a small probe clipped to the condenser coil tubing or fins with two wires going to the PCB.
• Step 3 – Check attachment: Ensure the sensor is firmly in contact with the coil. Reattach with the original clip or aluminum tape if loose.
• Step 4 – Inspect wiring and connector: Follow the wires to the outdoor or main PCB. Check for damage and reseat the connector.
• Step 5 – Test sensor: With power off, disconnect the sensor and measure resistance. Compare to expected NTC values; replace if open or shorted.
• Step 6 – Replace sensor: Install a new Sencor condenser temperature sensor, securing it tightly to the coil.
• Step 7 – PCB replacement: If E3 remains after sensor replacement and wiring checks, the control PCB is likely defective and should be replaced by a technician.