Execution order
1. Never open the circuit or disconnect any air conditioning system components before discharging the system.
2. After disconnecting the air conditioning system components, immediately close the connections with the appropriate caps to prevent moisture from the air from entering the system.
3. When installing new air conditioning system components, remove them from their packaging immediately before installation.
4. When connecting open fittings, always use new O-rings.
Information is taken from a thematic website (HYUNDAIBOOK)