What is one of the first steps to take when diagnosing a refrigerant leak?

One of the first steps to take when diagnosing a refrigerant leak is to look for oil residue. Refrigerants often carry a small amount of lubricant with them, and when a leak occurs, this lubricant can escape along with the refrigerant. Oil residue around connections, seams, or nearby components can indicate the presence of a leak. It is a practical and visual method to identify the potential source of the leak, which allows technicians to narrow down their investigation to specific areas of the system that are more likely to be affected.

Checking the compressor function and inspecting the evaporator are important steps in the overall diagnostic process but are more effective after identifying possible leak sources. Similarly, monitoring system pressure is crucial for assessing the overall health of the refrigerant system but does not directly lead to identifying a leak's location. Therefore, looking for oil residue serves as an efficient initial diagnostic step.