Unit frequently indicates 'ADD WATER' even though the reservoir is full.

Safety first: Unplug the unit and remove the water tank.

• 1. Clean float or probes: Remove the float and clean it and its guide with warm water and vinegar. For probe-type sensors, clean the metal rods.
• 2. Check free movement: Ensure the float moves smoothly from bottom to top without sticking.
• 3. Inspect wiring: Reseat the sensor connector on the harness and control board.
• 4. Test operation: Refill the tank, reinstall, and power on. If ADD WATER still appears, replace the water level sensor.

Warning: Do not bend sensor probes; this can change their calibration.