Unit displays E3 and may shut down cooling; fan may continue to run intermittently.

Safety: Unplug the unit. The condenser area is near the compressor and may contain hot surfaces; allow the unit to cool before working.

• Access rear/side panel: On portable Black+Decker units, remove the rear panel to access the condenser coil and compressor compartment. On window units, remove the outer shell as per the user manual.
• Locate condenser sensor: Find the small probe clipped to the condenser coil tubing or fins, usually near the middle or top of the coil, with two wires leading to the main PCB.
• Inspect mounting: Ensure the sensor is firmly attached to the coil. If it has fallen off, reattach it using the original clip or a metal clip rated for high temperature.
• Check wiring and connector: Look for melted insulation, chafed wires, or loose connectors. Reseat the connector on the main control board.
• Test sensor: With the sensor unplugged and the unit disconnected from power, measure resistance with a multimeter. Compare to the expected NTC thermistor values. Replace if open, shorted, or significantly off-spec.
• Reassemble and test: Install the new condenser thermistor if needed, secure wiring away from the fan and compressor, reassemble the cabinet, restore power, and verify that E3 clears.
• Control board check: If E3 persists with a new sensor, the main PCB is likely faulty and should be replaced by a professional.