Philips warm-mist humidifier shows F3 and shuts off; no steam is produced.

Safety: Unplug the unit and allow it to cool completely before opening. Hot steam can cause burns.

• Check water level: Ensure the tank is full and properly seated so water can flow into the boiling chamber.
• Descale heating chamber: Remove the tank and access the heating chamber. Fill with a mixture of white vinegar and water and let soak to dissolve limescale. Rinse thoroughly afterward.
• Inspect outlets: Make sure the steam outlet and any air channels are not blocked by mineral deposits or foreign objects.

If F3 continues, the temperature sensor or thermal fuse may have failed. These are safety-critical components and should be replaced by a qualified technician using Philips-approved parts.