First, identify the type of noise. A single "di" sound when you press a button is normal. A continuous hum varies by fan speed.
- Check for obstructions. Ensure nothing is touching the fan inside. Make sure the front cover is securely clicked into place. An improperly seated cover or filter can cause vibration.
- Clean it. Dust buildup on the fan or internal components can cause noise. Unplug the unit, remove the front cover and filter, and check for debris. Use a dry cloth to wipe the interior.
- Listen to the motor. A consistent hum on High speed is typical for the AC motor. If the noise is a loud grinding, rattling, or clicking, the fan or motor bracket may be damaged. Do not disassemble the appliance yourself.
If the noise persists after cleaning and ensuring everything is seated properly, contact customer service. Don't continue using a unit making abnormal mechanical noises.