Which type of mobile ac system will usually require additional time precautions to extract all of the refrigerant?

Recovery of refrigerant from a mobile air conditioning (AC) system that uses R-134a typically requires additional time precautions. This is due to the need for thorough recovery to ensure all refrigerant is extracted, as residual refrigerant can remain in the system. Additionally, systems with larger refrigerant charges or those that are older may also require more time for complete recovery, as they may have more complex components or potential leaks. Proper recovery procedures are critical to prevent environmental harm and comply with regulations.