The surface that the air conditioner is on may not be level or flat enough. Place the unit on a flat, level surface if possible.
Other causes could be:
- Misaligned fan. A fan could be misaligned or improperly installed inside the unit. In this case, contact a local service center or Customer Service for repair.
- Damaged motor or compressor. Loud rattling or vibration could be caused due to damaged parts inside the unit. Contact Customer Service.