E1 displayed and unit stops cooling intermittently

Safety first: Disconnect power before opening the cabinet. Sensors are low voltage but the unit contains high-voltage components.

• Step 1 – Reset and inspect:
  • Unplug the unit for 5 minutes and plug back in.
  • If E1 returns quickly, proceed to sensor inspection.
• Step 2 – Locate ambient sensor:
  • Remove the front grille or filter cover.
  • On most Pro Breeze portable and window units, the room sensor is a small probe or plastic-encased thermistor near the air intake behind the filter, connected by two thin wires to the control board.
• Step 3 – Check wiring:
  • Ensure the sensor plug is firmly seated on the main PCB.
  • Inspect the sensor lead for cuts, pinches, or corrosion.
• Step 4 – Test/replace sensor:
  • If you have a multimeter, measure resistance across the sensor leads; it should change smoothly with temperature (typically 5–20 kΩ range). An open circuit or 0 Ω indicates failure.
  • Order a compatible Pro Breeze Ambient Temperature Sensor / NTC Thermistor for your model.
  • Unplug the old sensor, route the new one along the same path, and secure it away from the evaporator coil to sense room air.

If replacing the sensor does not clear E1, the sensor input on the main PCB may be defective and the board will need replacement.