Check local codes, permits, and manufacturer requirements
Choose the correct mini split size and system type
Select indoor and outdoor unit locations
Verify wall strength, clearances, and drainage path
Gather tools, mounting hardware, refrigerant line set, electrical supplies, and condensate drain materials
Turn off power at the breaker
Mount the indoor unit bracket level on the wall
Drill a hole through the wall for the line set, drain, and wiring
Install the wall sleeve or grommet in the hole
Route the refrigerant lines, drain line, and communication cable through the wall opening
Mount the indoor unit on the bracket
Place and secure the outdoor condenser on a pad or brackets
Connect the refrigerant lines to the indoor and outdoor units
Tighten flare fittings to the specified torque
Connect the communication wiring between indoor and outdoor units
Connect the condensate drain line with proper slope
Connect the electrical supply and disconnect according to code
Install the outdoor service disconnect and breaker if required
Evacuate the line set with a vacuum pump
Check for leaks with a pressure test or leak detector
Open the refrigerant service valves
Restore power to the system
Test cooling and heating operation
Verify airflow, drainage, and error codes
Seal the wall penetration and secure all lines
Insulate exposed refrigerant lines
Clean up the installation area