The "warning" sensor is triggered when it detects water at the base of the unit. This feature is designed to prevent flooding in your home. However, sometimes the warning may activate even when there isn't an actual leak. Here are some possible reasons why this might happen: The most common cause is improper placement of the rear funnel. The funnel must be properly aligned in its tracks, as it channels the freshly generated water into the lower container. If it's misaligned, water can escape elsewhere, triggering the warning. Another potential cause is the lack of cleaning of the carbon basket. Over time, dirt accumulates and clogs the pores, causing the water to overflow instead of flowing correctly into the lower tank. It's also common for the warning to activate hours or days after performing the weekly cleaning. Even if the unit is turned off, water may continue to drip from the condenser. This water should fall into the funnel and then into the lower container. However, if you remove the funnel and the lower container during cleaning, the dripping water has nowhere to go but the base, eventually reaching the sensor and activating the warning.