What are the two basic types of recovery devices?

The correct response identifies the two basic types of recovery devices as Self-Contained and System-Dependent.

Self-Contained recovery devices operate independently of the HVAC or refrigeration system. They have their own means of obtaining refrigerant from the system and processing it. This means these devices can be used to recover refrigerants regardless of the type of equipment they are servicing, making them versatile for various applications, regardless of system design.

On the other hand, System-Dependent recovery devices require the system's pressure to assist in the recovery process. These devices rely on the refrigerant existing in the system under certain operating conditions to facilitate the recovery. As a result, they're typically used on systems that can provide enough pressure for effective recovery.

Considering the nuances of refrigerant recovery, it’s vital to distinguish between these types, as they indicate how a technician might select a device based on the specific context of the recovery task.

The other options such as Portable and Stationary refer to the physical mobility of the equipment rather than the functional operation principles. High Pressure and Low Pressure categorize based on the refrigerant pressures being worked with but do not define the operational method of recovery devices. Likewise, Automated and Manual describe the method of operation but again do not capture the fundamental differences