Technician A says the presence of oil around a fitting of an air-conditioning line may indicate an oil leak but not a refrigerant leak. Technician B says using an electronic leak detector is the best way to find the source of a refrigerant leak. Who is correct?

Using an electronic leak detector is indeed recognized as one of the most effective methods for locating refrigerant leaks in air-conditioning systems. These detectors are designed to sense the specific characteristics of refrigerants, allowing technicians to identify leaks more accurately and with greater sensitivity than traditional methods. This makes them a preferred tool in the industry, as refrigerants can pose safety and environmental risks if not managed properly.

On the other hand, while the presence of oil around a fitting might suggest an oil leak, it is not an absolute indication of the absence of a refrigerant leak. In many cases, refrigerant leaks can accompany oil leaks since refrigerant can carry oil with it as it escapes from the system. Therefore, while Technician A's statement about the presence of oil indicating an oil leak has some merit, it does not comprehensively address the relationship between oil and refrigerant leaks, as the two can occur simultaneously.

This distinction highlights why Technician B’s assertion stands stronger in the context of leak detection. Using specialized tools like electronic leak detectors enhances the capability to locate and address refrigerant leaks effectively, which is crucial for maintaining the efficiency and safety of air-conditioning systems.