Humidifier fan runs but there is no visible mist and no increase in humidity (evaporative models like Oskar, Karl)

Safety: Unplug the unit and remove the water tank.

• Remove filter cassette: Lift out the evaporative filter pack from the base.
• Inspect condition: If the filter is stiff, brown, or has a strong odor, it is beyond cleaning and must be replaced with a genuine Stadler Form filter.
• Temporary rinse: If only lightly soiled, rinse the filter under cool running water to remove loose debris. Do not use hot water or detergents, which can damage the fibers.
• Clean tray: Wipe the filter tray and base with a mild vinegar solution to remove slime and scale, then rinse.
• Reinstall correctly: Ensure the new or cleaned filter sits flat and fully submerged when the tank is installed, so the fan can draw air through it.