Loud rattling or buzzing noise from the indoor unit during operation.

Safety: Turn off power before touching the unit.

Steps:

• Tighten panels: Ensure the front cover is fully closed and latched. Check that filters are seated correctly.
• Check mounting: Gently push on the indoor unit. Excessive movement indicates loose mounting screws or a bent wall plate; tighten or refix as needed.
• Inspect blower: Remove the front cover and look for objects inside the blower area. Remove any debris.
• Clean blower: If the blower is heavily caked with dust on one side, clean it to restore balance.
• Persistent noise: If noise continues, the blower wheel or motor bearings may be worn and require replacement.