Excessive vibration or rattling of the outdoor unit, transmitted into the building structure.

Safety: Turn off power before working around the outdoor unit. Heavy units can shift unexpectedly.

Steps:

• 1. Check level: Place a spirit level on top of the outdoor unit. Adjust the base or brackets so the unit is level.
• 2. Inspect mounting pads: Ensure rubber pads are present under the unit feet. Replace cracked or missing pads with new anti-vibration pads.
• 3. Tighten bolts: Tighten all mounting bolts securing the unit to its base or wall brackets.
• 4. Fan balance: Inspect the fan blade for damage or missing pieces. Replace if unbalanced.
• 5. Structural isolation: If mounted on a wall, consider adding vibration isolators or relocating the unit to reduce noise transmission.