The unit is very noisy during operation; rattling or buzzing sounds come from inside.

Safety: Unplug the unit before opening. Beware of sharp metal edges.

Steps:

• External check: Ensure the unit is on a solid, level surface. Place a thin rubber mat under the unit to reduce vibration.
• Inspect fan: Remove the front cover and check that the fan wheel is firmly attached to the motor shaft. Tighten the set screw or clip if loose.
• Compressor mounts: Access the base of the unit and inspect the rubber compressor mounts. Tighten mounting bolts if they are loose, but do not overtighten and crush the rubber.
• Cabinet panels: Press gently on different panels while the unit runs (use caution around moving parts) to identify vibrating sections. Add foam tape or tighten screws where needed.