Dehumidifier beeps and shows E3; compressor does not start.

Safety: Unplug the unit before removing any covers. Avoid touching the PCB with wet hands.

Steps:

• Reset attempt: Unplug for 5–10 minutes, then plug back in. If E3 reappears immediately, proceed.
• Access the humidity sensor: Remove the front grille or control panel bezel. On many Challenge models, the humidity sensor is a small plastic module with vents, located near the air intake or behind the control panel.
• Inspect the sensor: Check for dust buildup, corrosion, or signs of water damage. Gently clean the sensor vents with a soft brush or compressed air (do not use liquid cleaners).
• Check wiring: Follow the sensor cable to the main PCB. Ensure the connector is fully seated and the cable is not pinched or cut.
• Replace the sensor if faulty: If the sensor housing is cracked, corroded, or E3 persists after cleaning and reseating, replace it with a compatible Challenge humidity sensor module. Disconnect the old module, mount the new one in the same location, and plug into the PCB.
• Reassemble and test: Refit the front grille and control panel, restore power, and test operation. The E3 code should clear automatically.

Tip: If the new sensor does not resolve E3, the control PCB may not be reading the sensor correctly and may need replacement.