What is the first step when servicing an air-conditioning system that has lost all of its freon?

When servicing an air-conditioning system that has lost all of its freon, the first step involves checking the oil and adding it as necessary. This is crucial because the refrigerant, in this case, freon, not only cools the air but also lubricates the compressor. If the system has lost all of its refrigerant, it's likely that the compressor may have run without sufficient lubrication, which could lead to component damage. Ensuring the oil level is adequate before any further steps can help prevent further issues and protect the compressor when reintroducing refrigerant.

In practice, inspecting the oil allows technicians to identify potential problems that may have caused the loss of freon. It establishes a baseline for maintaining system integrity before proceeding with any repairs or refrigerant addition. Adding freon directly without checking the oil could exacerbate any underlying problems, such as damage to the compressor or oil starvation, leading to more significant failures in the future.