Safety: Unplug the humidifier and empty all water before opening the base.

Steps:

Visual inspection: Locate the ultrasonic transducer (metal disc at the bottom of the water chamber). Check for cracks, discoloration, or heavy white mineral deposits.
Clean transducer: Soak a cotton swab in white vinegar and gently wipe the disc surface to remove scale. Do not press hard or use sharp tools.
Check wiring: From the underside (after removing the base cover), inspect the two wires leading to the transducer. Ensure the connector is firmly seated on the PCB and wires are not broken.
Test after cleaning: Reassemble, refill, and power on. If E5 remains, the transducer or driver circuit is likely defective.
Replace transducer module: Replace the ultrasonic transducer assembly (often mounted on a small plate with gasket). Ensure the sealing gasket is properly seated to prevent leaks.
Control board: If a new transducer does not resolve E5, replace the main control board which contains the ultrasonic driver.

Levoit humidifier displays E5 and will not produce mist.

Possible Causes