When can appliances containing CFC refrigerants be evacuated to atmospheric pressure?

Evacuating appliances containing CFC refrigerants to atmospheric pressure is only permissible under specific conditions, primarily to minimize environmental harm associated with refrigerant release. The correct choice indicates that evacuation to atmospheric pressure is acceptable when leaks make it impossible to reach the prescribed evacuation level. In such circumstances, it becomes challenging to recover the remaining refrigerant adequately, and attempting to bring the system to the mandated level could result in more refrigerant escaping into the atmosphere.

Proper adherence to regulations, such as those set forth by the Environmental Protection Agency (EPA), is crucial. These regulations are designed to safeguard the environment by preventing harmful substances, like CFCs, from being released. When leaks are present, there may be no practical way to recover refrigerants completely; thus, making the conditions under which evacuation occurs more forgiving under these specific circumstances.

This choice highlights the importance of understanding the practical limitations faced by technicians in the field, particularly when dealing with aging or compromised systems.