Dyson humidifier shows F4 and stops operation, often after a short run time

Safety first: Unplug the humidifier and allow it to cool for at least 20 minutes before inspection.

• 1. Check airflow: Inspect all air intake grilles and exhaust outlets for dust, pet hair, or obstructions. Use a soft brush or vacuum with a brush attachment to clean them thoroughly.
• 2. Verify fan operation: With the unit reassembled, plug it in and start it on a low setting. Listen for the internal fan. If the fan does not run or sounds weak, the unit may overheat and trigger F4.
• 3. Clean internal passages (non-invasive): Without opening the case, blow compressed air gently through the vents to clear internal dust. Do not use high pressure that could damage components.
• 4. Sensor fault: If F4 appears immediately on startup, the NTC temperature sensor or its wiring may be open or shorted. This requires disassembly of the base and replacement of the sensor or PCB, which is best handled by a technician.

Warning: Do not bypass or short any thermal safety devices. They are critical for fire safety.