Humidifier displays F1 and stops mist production.

Safety: Turn off and unplug the Klarstein humidifier before removing the tank.

• Check tank position: Remove and reinstall the water tank, ensuring it sits flat and fully engages any locating pins or valves. Many Klarstein humidifiers use a magnet in the tank that must align with a reed switch in the base.
• Refill tank: Ensure the tank is filled above the minimum level mark. Some models will show F1 if the level is too low to feed the ultrasonic transducer.
• Inspect float/magnet: If the tank has an internal float, verify it moves freely and is not stuck by scale or debris. Clean with warm water and vinegar if necessary.
• Check base sensor: Look into the base for the reed switch or level sensor. Wipe away any mineral deposits or rust with a soft cloth and a bit of white vinegar, then dry thoroughly.
• Replace sensor: If F1 persists and the tank and float are fine, the reed switch or level sensor module in the base may be defective and should be replaced with a Klarstein-compatible part.