Diagnosis
The water level sensor float in the clean water tank is stuck in the 'low' position, or the tank is not seated correctly on the sensor pins.
How to Fix It
Reset the tank sensor. Step sequence: 1. Remove the clean water tank from the dock. 2. Shake the tank and listen for the internal float moving freely. 3. Look through the transparent side to see if the white float is at the bottom. Manually tilt the tank to free it if stuck. 4. Reinstall the tank, pressing down firmly on the dock until you hear a distinct click.
If That Didn't Work
The electrical contacts on the dock or tank are dirty. Power off, unplug the dock, and clean the four small metal contact pins on the dock base and the corresponding pads on the tank with a dry cloth.
Heads Up
Only use the official cleaning solution or clear water. Thick or sugary solutions can gum up the float mechanism and sensor.