Dehumidifier stops and shows H21; water tank may not be full.

Safety first: Unplug the unit before removing the water tank.

• Empty and clean tank: Remove the water tank, empty it, and clean any slime or mineral buildup that could jam the float.
• Check float movement: Locate the float inside the tank or in the tank compartment. Move it up and down; it should move freely and return under its own weight.
• Inspect tank seating: Reinstall the tank firmly. Ensure it is fully inserted so that the tank tab correctly actuates the tank full switch.
• Test the switch: With the unit unplugged, access the tank full micro-switch. Manually press the actuator and check continuity with a multimeter. Replace the switch if it does not change state.
• Replace float assembly: If the float is waterlogged, cracked, or missing its magnet, install a new Panasonic float/tank sensor assembly.