What does self-contained or active recovery equipment use for refrigerant recovery?

Self-contained or active recovery equipment is designed to effectively recover refrigerant by having its own built-in means to do so. This equipment often features a compressor that actively removes refrigerant from the system, allowing for efficiency and rapid recovery. The active nature of such equipment means it can effectively draw refrigerant into its storage tank, eliminating the need for external assistance or additional components to facilitate the recovery process.

The other options mention various attributes, such as charcoal bag filters, liquid rate capabilities, and vacuum pump requirements, but these do not accurately describe the function or capabilities of self-contained recovery systems. In contrast, the correct choice clearly identifies the independence and functionality of the equipment in recovering refrigerant on its own. Understanding this helps clarify why self-contained recovery equipment is essential in refrigerant management and safety practices.