What should be done before removing a compressor from a system containing R404A?

Before removing a compressor from a system containing R404A, it is essential to isolate the compressor. Isolating the compressor involves shutting off the valves that control the flow of refrigerant to and from the compressor, preventing refrigerant from circulating through the system during the removal process. This step is critical for safety reasons, as it helps to avoid refrigerant leaks and potential exposure to harmful substances.

Additionally, isolating the compressor ensures that the system's remaining components are not disturbed or damaged during the removal. It also helps maintain system integrity, as well as pressure and temperature stability in other parts of the HVAC system that may still be operational.

Other options, like opening the system to atmospheric pressure or charging the system with refrigerant, can create risks such as leaks or contamination. Cleaning the compressor connections is a good maintenance step but is not a primary action that should be taken before removal. The focus should be on isolating the compressor effectively to ensure a safe and efficient removal process.