Humidifier stops and displays E2; unit may start then shut down after a few seconds.

Safety: Disconnect the humidifier from power before opening the housing.

• Reset: Unplug for 5–10 minutes, then reconnect. Check if E2 clears.
• Locate humidity sensor: On many Medisana humidifiers, the humidity sensor is a small plastic module near the air outlet or intake, connected by a 3–5 wire harness to the PCB.
• Check connection: Ensure the sensor plug is fully inserted into the main PCB and that no pins are bent. Inspect the cable for cuts or pinch points.
• Clean sensor area: If the sensor is covered in white mineral dust or oily residue, gently clean the surrounding plastic with a dry soft brush. Do not soak the sensor in water; a light wipe with a barely damp cloth around (not on) the sensor opening is acceptable.
• Replace sensor: If E2 remains, replace the humidity sensor module with a Medisana-compatible humidity sensor assembly. Match the part by model number.
• PCB fault: If a new sensor does not resolve E2, the main control PCB is likely defective and should be replaced by a service technician.