Humidifier shows F5 and will not produce mist, even though the fan may run.

Safety: Unplug the unit and empty the water tank before inspection.

• Check water quality: Use clean, preferably demineralized water. Hard water can cause mineral buildup on the ultrasonic membrane.
• Clean the nebulizer: Locate the ultrasonic membrane at the bottom of the water basin. Gently clean it with a soft cloth or cotton swab dipped in white vinegar, then wipe with clean water. Do not press hard on the membrane.
• Dry the basin: Ensure no water has leaked into the electronics compartment beneath the basin. If you see moisture, allow the unit to dry completely for 24 hours before retrying.
• Inspect for cracks: If the membrane is visibly cracked or detached, the atomizer assembly must be replaced.
• If F5 persists: The ultrasonic driver circuit on the PCB or the atomizer module is defective. Replacement requires disassembly and should be done by a qualified technician.