Levoit humidifier displays E3 and mist output stops or never starts.

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

Steps:

• Clean float assembly: Remove the tank and locate the float chamber in the base (often a plastic well with a floating ring or cylinder). Lift out the float and clean it with warm water and mild dish soap. Remove any scale or slime.
• Clean float well: Wipe the inside of the float chamber and the reed switch area (usually a small plastic housing on the side of the well) to remove mineral deposits that can block movement or magnetic sensing.
• Check float movement: Reinstall the float and verify it moves freely up and down without sticking.
• Inspect wiring: If accessible, check the two‑wire harness from the float/reed switch to the main PCB for damage or loose connectors.
• Test with full tank: Refill the tank, reinstall, and power on. If E3 remains, the reed switch or electronic level sensor is likely faulty.
• Replace sensor: Replace the water level sensor assembly (float + reed switch or electronic probe) with a compatible Levoit part. If the sensor is integrated on the main PCB, the entire board may need replacement.