How to Fix / Troubleshooting

Safety first: Unplug the unit before removing the control panel.

Dry the panel: If the panel has been exposed to water spills or high condensation, allow it to dry completely for several hours with the unit unplugged.
Inspect the ribbon cable: Remove the control housing and locate the flat ribbon cable or harness connecting the keypad to the main board. Reseat both ends firmly.
Check for corrosion: Look for green or white corrosion on connectors. Lightly clean with electronic contact cleaner and a soft brush if present.
Test keypad buttons: With the unit reassembled and plugged in, press each button to see if it responds. If some buttons are dead or E4 persists, the keypad membrane may be faulty.
Replace control panel if needed: Order the correct Essick Air control panel or keypad assembly by model number and swap it, transferring any mounting hardware.

If a new keypad does not resolve E4, the main control board may be defective and should be replaced or serviced professionally.

Essick Air digital humidifier shows E4 and may shut down or fail to respond to keypad inputs.

Possible Causes