Homedics ultrasonic humidifier shows E3 and stops producing mist; fan may still run.

Safety: Unplug the humidifier and remove the water tank. Never work on the unit while it is powered or filled.

Steps to fix E3:

• Clean the float assembly: On many Homedics ultrasonic models, the water level is detected by a float in the base. Remove the tank and locate the float (usually a plastic ring or capsule). Lift it gently and check for mineral buildup. Clean with a 1:1 white vinegar and water solution, then rinse and dry.
• Check float movement: Ensure the float moves freely up and down and is not obstructed by debris or misaligned parts.
• Inspect sensor contacts: Some models use metal level probes. Wipe them with a vinegar-dampened cloth to remove scale, then wipe dry.
• Verify wiring: If accessible, remove the base cover and inspect the float switch wiring harness to the main PCB. Ensure connectors are fully seated and wires are not broken.
• Test the float switch (advanced): With the unit unplugged, disconnect the float switch and measure continuity with a multimeter while moving the float. It should change state (open/closed) as the float moves.
• Replace faulty parts: If the float is waterlogged, cracked, or the switch tests bad, replace the Homedics float switch / water level sensor assembly for your model.
• If E3 remains: The water level detection circuit on the main control PCB may be defective, requiring board or unit replacement.