Dehumidifier shows E3 and the compressor does not run, or unit cycles off quickly.

Safety first: Unplug the unit. The evaporator coil edges can be sharp; wear cut-resistant gloves.

Steps to fix:

• 1. Access the evaporator coil: Remove the front or rear cover to expose the evaporator (cold) coil. The coil temperature sensor is usually clipped to the coil tubing or fins.
• 2. Inspect sensor placement: Ensure the sensor is firmly attached to the coil surface. A loose sensor can misread temperature and trigger E3.
• 3. Check wiring and connector: Follow the sensor wires back to the main control board. Look for insulation damage, pinched wires, or corrosion at the connector. Reseat the connector.
• 4. Test the thermistor: Disconnect the sensor and measure resistance with a multimeter. Compare to the Carrier spec chart for the coil sensor. Replace if reading is open, shorted, or far out of range.
• 5. Replace sensor if needed: Order the Carrier evaporator thermistor for your model. Clip it securely to the same coil location and route wires away from the fan blade.
• 6. Evaluate the control board: If the sensor tests good and wiring is intact, the main control board may be misreading the sensor. Inspect for damage and replace the board if E3 persists.

Tip: After replacement, run the unit and verify that the coil gets cool but does not ice over excessively.