Indoor unit displays E3; outdoor unit may not start or shuts down shortly after starting.

Safety: Disconnect power at the outdoor disconnect or breaker before opening the outdoor Senville condenser.

• Step 1 – Open outdoor unit: Remove the service panel to access the control board and wiring.
• Step 2 – Locate T2 sensor: Find the small probe clipped to the outdoor condenser coil or attached to the refrigerant line. Follow its wires to the outdoor PCB.
• Step 3 – Inspect wiring and connector: Check for corrosion, loose pins, or broken insulation. Reseat the connector on the PCB.
• Step 4 – Check sensor mounting: Ensure the sensor is firmly attached to the coil or line and not dangling in free air.
• Step 5 – Replace sensor: If the sensor is cracked, corroded, or E3 persists, replace it with the correct Senville outdoor coil sensor. Secure the new sensor in the same location and route wiring away from moving parts.
• Step 6 – PCB evaluation: If a new sensor does not resolve E3, the outdoor PCB may be faulty and should be diagnosed by a professional.