CFCs are chlorofluorocarbons—refrigerants that contain chlorine and fluorine bonded to carbon, with no hydrogen. This structure is why they are associated with ozone depletion. Among the options, the classic examples of CFCs are R11 and R12 (trichlorofluoromethane and dichlorodifluoromethane). The other refrigerants belong to different families: R22 is an HCFC, which has chlorine but also hydrogen, so it isn’t a true CFC; R134a and R410A are HFCs, containing fluorine and hydrogen but no chlorine, so they aren’t CFCs.

Reclaimed refrigerant must meet a defined purity standard before it can be resold. AHRI Standard 700 specifies those purity requirements, outlining acceptable levels of moisture, acidity, non-condensables, and other contaminants, as well as the overall composition of the refrigerant. Meeting these specifications ensures the reclaimed product will perform reliably in systems and won’t cause corrosion, deterioration, or operational problems. The other options don’t set the purity criteria for reclaimed refrigerants: EPA 608 relates to technician certification and handling, ISO 9001 is about quality management systems, and UL 94 covers flammability ratings for plastics.

When air ends up in the refrigerant circuit, it becomes a non-condensable gas that doesn’t liquefy in the condenser. This gas collects around the condenser tubes and forms an insulating layer, which greatly reduces the condenser’s ability to reject heat. With poorer heat rejection, the condenser pressure (the head pressure) rises, and the compressor has to push against that higher pressure, causing the discharge pressure to climb. This is a common and direct way discharge pressures can go up. While other factors can influence pressures—for example, an overcharged refrigerant system, slower compressor speeds, or higher ambient temperatures—the presence of air in the system specifically leads to a rise in discharge pressure by hindering heat transfer and raising the condensing pressure.

When a deep vacuum is present, any moisture in the system is exposed to very low pressure and extreme cooling as liquid refrigerant is introduced. That cold, moisture-laden environment causes the water in the system to freeze, forming ice inside lines, filters, or metering devices. This ice can restrict flow and disrupt the system’s operation, which is why the outcome described is that the system water freezes. Other issues like oil acidity, overheating, or refrigerant instability aren’t the immediate effect of charging under this level of vacuum.