Dehumidifier displays E3 and shuts down or fails to start the compressor; fan may operate.

Safety: Unplug the unit before removing the control panel or front grille.

Steps:

• Power cycle: Disconnect power for 5 minutes and restart. If E3 reappears, continue.
• Locate humidity sensor: On Honeywell dehumidifiers, the RH sensor is usually behind the front grille or integrated into the control panel area, exposed to room air via small vents.
• Clean sensor area: Use compressed air or a soft brush to remove dust and lint from the sensor opening. Do not spray liquids directly into the sensor.
• Check wiring: Remove the control panel cover and verify the sensor harness is firmly connected to the main PCB. Look for corrosion or broken wires.
• Replace sensor: If the sensor is visibly damaged or E3 persists after cleaning and reseating, replace the humidity sensor assembly with a Honeywell‑compatible part.
• Control board: If a new sensor does not clear E3, the main control board is likely faulty and should be replaced.

Tip: After replacement, verify that the displayed humidity changes when you introduce moist air (e.g., by briefly exhaling near the intake) to confirm sensor operation.