Who is correct about what it means if a system does not hold a vacuum during a standing test?

A system that fails to hold a vacuum during a standing test indicates that there is a leak in the system. This is a critical aspect of diagnosing issues in HVAC systems. Holding a vacuum is essential for confirming the integrity of the system, particularly when working with refrigerants. If a vacuum cannot be maintained, it suggests that air and moisture could enter the system, which can lead to further complications, such as reduced efficiency, freezing of coils, or even equipment damage.

Typically, Technician "A" would correctly identify that the inability to maintain a vacuum is a clear sign of a leak—whether it be in the refrigerant lines, seals, or fittings. This understanding is foundational for HVAC technicians as it directs them to take steps to find and repair the leak before proceeding with the system's operation.

On the other hand, if either technician provides reasoning that does not align with the fundamental principles of vacuum testing or the implications of those results, that reasoning would not hold true in the context of standard HVAC practices. Thus, the clarity provided by Technician "A" represents a critical understanding of what a vacuum failure indicates regarding system integrity and necessary service actions.