Dehumidifier shows E3 and will not start the compressor; fan may still operate

Safety: Always unplug the dehumidifier before removing covers or touching internal components.

Steps to troubleshoot E3 (humidity sensor):

• 1. Basic reset: Disconnect power for 5–10 minutes, then reconnect. If E3 persists, continue.
• 2. Locate the humidity sensor: On many Ariston units, the humidity sensor is mounted behind the front grille or integrated into the air intake area, connected to the control board by a small harness.
• 3. Inspect the sensor area: Remove the front grille or filter. Look for a small plastic module or PCB with vents. Check for dust buildup, moisture, or corrosion.
• 4. Clean the sensor gently: Use dry compressed air or a soft brush to remove dust. Do not spray liquids directly on the sensor.
• 5. Check wiring and connector: Follow the sensor wires to the main PCB. Ensure the connector is fully seated and free of corrosion. Reseat it several times to improve contact.
• 6. Replace the sensor if needed: If E3 remains and the wiring is intact, replace the Ariston humidity sensor module with the exact part specified for your model. Mount it in the same orientation to ensure accurate readings.
• 7. Main board check: If a new sensor does not clear E3, the humidity sensing circuit on the main control board may be defective, requiring board replacement by a professional.