All liquid has been recovered from a system to be overhauled; the system

• A. Should not be opened until all vapor has been recovered
• B. The system may be opened after the liquid is recovered
• C. The system should be depressurized and opened
• D. The system should be filled with inert gas before opening

Answer: (A)

Before opening a system for overhaul, all refrigerant must be removed from both liquid and vapor phases. Even when the liquid has been recovered, there can still be vapor inside the system under pressure. Opening the system at this point would cause a rapid release of refrigerant vapor into the room, which can be dangerous to the technician and harmful to the environment. The proper step is to continue the recovery process to capture that remaining vapor, bringing the system to atmospheric pressure and ensuring the work area stays safe and compliant with regulations. Only after the vapor is recovered should the system be opened for service.