Dehumidifier display shows E2 and unit will not start or shuts down shortly after starting.

Safety first: Disconnect power before accessing internal components. The compressor and fan can start unexpectedly if power is applied.

Steps to diagnose and correct:

• 1. Power reset: Unplug the unit for 5 minutes and plug back in. If E2 returns immediately, proceed with sensor checks.
• 2. Locate the ambient thermistor: On Carrier dehumidifiers, the room temperature sensor is usually clipped near the air intake grille or on the evaporator inlet tube. It is a small bead or bullet-shaped sensor with two wires leading to the main board.
• 3. Inspect wiring: Check the sensor leads for cuts, pinches, or pulled-out connectors. Ensure the plug is fully seated on the main control board.
• 4. Test the thermistor: With the unit unplugged, disconnect the thermistor from the board and measure its resistance with a multimeter. Compare the reading to Carrier’s thermistor chart (for many NTC sensors, ~10kΩ at 77°F/25°C). If the reading is near 0Ω (short) or infinite (open), the sensor is defective.
• 5. Replace the thermistor: If faulty, order the correct Carrier ambient thermistor for your model. Clip or strap the new sensor in the same location and route the wires away from sharp metal edges and moving parts.
• 6. Check the control board: If the thermistor tests good and wiring is intact, the temperature input circuit on the main control board may be defective. Inspect for burnt components; replace the board if necessary.

Note: Operating with a bypassed or incorrect sensor can cause coil icing or poor humidity control. Always use the correct Carrier sensor.