After removing an expansion valve, which action should a technician take in regards to the refrigeration system?

After removing an expansion valve, the correct action for a technician is to close all suction line manifold valves. This is essential to prevent any refrigerant from escaping from the system and to ensure that no contaminants enter the suction lines while the valve is removed. Closing the valves helps to maintain system integrity and pressure.

It's crucial for the technician to ensure that these valves are closed while work is being done on the system; otherwise, there may be risks of refrigerant leakage or air and moisture entering the system, which can lead to compressor damage or operational issues once the expansion valve is replaced. This practice is standard safety and operational procedure in refrigeration system maintenance.

Other actions, such as opening the manifold valves or leaving them in a mid-position, could expose the system to potential risks, making it unclear whether the system can be safely worked on or whether it will function properly when reassembled. Checking the liquid receiver service valve does not directly address the immediate concern after the removal of an expansion valve. Hence, closing all suction line manifold valves is the most appropriate and crucial step.