Turn off the AC unit and disconnect power
Check the refrigerant type on the unit nameplate
Inspect for leaks and repair any found before charging
Connect manifold gauges to the service ports
Attach a refrigerant charging hose and vacuum pump if needed
Evacuate the system if it has been opened or is low due to repair
Confirm the correct charging method for the system
Charge by weight using the manufacturer’s specified amount
Add refrigerant slowly in small amounts
Monitor suction and discharge pressures during charging
Check superheat or subcooling as required by the system
Stop charging when the specified values are reached
Disconnect the gauges and replace service port caps
Restore power and test the AC operation
Verify proper cooling and normal system performance
Use only a licensed HVAC technician if required by local law