Humidifier shows H1 and stops adding moisture.

Safety: Unplug before handling internal switches.

Steps:

• Refill tank: Remove the water tank, fill to the indicated level, and reinstall firmly.
• Check tank seating: Ensure the tank is fully pushed down and aligned with the base so that the valve opens and the switch is actuated.
• Inspect tank float: If the tank has an internal float, make sure it moves freely and is not stuck in the empty position.
• Test tank switch: Locate the tank presence or level switch on the base. Press it manually and listen for a click. Replace with a Challenge humidifier tank switch if it fails.