Final answer:
The correct action after reaching the required recovery vacuum on an appliance is usually to add more refrigerant, after ensuring the system holds the vacuum and has no leaks.
Step-by-step explanation:
After reaching the required recovery vacuum on an appliance, the next step is typically to ensure that the system does not have leaks. This is often done by performing a vacuum hold test to see if the system maintains the vacuum over a set period. If the vacuum level holds, it implies there are no significant leaks, and the technician can proceed with charging the system with refrigerant.
Therefore, the correct answer to the question is not to increase the temperature, shut off the appliance, or decrease the pressure. Instead, the correct course of action is usually C) Add more refrigerant. Once the system is charged with the correct amount of refrigerant, it can be started up and returned to normal operation.