Beurer ultrasonic humidifier displays E3 and does not generate mist.

Safety: Unplug the unit and empty the water tank before working on it.

What to check:

• Confirm water level: Ensure the tank is filled to at least the minimum mark and properly seated on the base. Many Beurer models will show E3 if the tank is not correctly positioned.
• Inspect the float: Look inside the base or tank (depending on model) for a plastic float that moves up and down with water level. Make sure it moves freely and is not jammed by limescale or debris.
• Clean the float chamber: Remove the float (if removable) and soak in a 1:1 mixture of white vinegar and water for 20–30 minutes to dissolve scale. Rinse thoroughly and reinstall.
• Check level sensor contacts: Some Beurer units use metal probes in the base. Clean them gently with a soft cloth and vinegar to remove mineral deposits, then wipe dry.
• Inspect wiring: Remove the bottom cover and trace the float switch wires to the PCB. Ensure the connector is secure and wires are not broken or pinched.
• Test the float switch (advanced): With the unit unplugged, disconnect the float switch and check continuity with a multimeter while moving the float. It should switch between open and closed. If it does not change, replace the float switch assembly.

If E3 remains: The water level detection circuit on the main PCB may be defective and should be serviced by a professional.