Dyson humidifier shows F12 and will not start, often after a power surge or outage

Safety first: Unplug the unit before extended resets.

• 1. Hard power reset: Unplug the humidifier for at least 15 minutes. Press and hold the power button (if accessible) for 10 seconds while unplugged to help discharge internal circuits. Then plug back in and test.
• 2. Check for firmware update: If your model supports app connectivity, see if a firmware update is offered. Follow Dyson's instructions carefully.
• 3. Surge protection: If F12 appeared after a storm or outage, plug the unit into a known-good surge protector and test again.
• 4. Service mode (if documented): Some models have a service reset sequence (e.g., holding specific buttons). Only use procedures documented in the official manual.
• 5. Board replacement: If F12 persists, the main control PCB or its memory components are likely damaged and must be replaced by a professional.