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

After removing an expansion valve, the appropriate action is to close all suction line manifold valves. This step is crucial to prevent the potential for refrigerant leaks and to protect the integrity of the refrigeration system while maintenance or repairs are being performed.

Closing the suction line manifold valves effectively isolates the system and prevents any unintended flow of refrigerant into or out of the affected area, which could lead to safety hazards, system contamination, or improper operation after reassembly. Additionally, it provides a controlled environment for any further diagnostics or repairs needed before the system is recharged with refrigerant.

In contrast, opening the manifold valves or leaving them in a mid-position could facilitate unwanted refrigerant movement, leading to loss of charge or system instability. Checking the liquid receiver service valve is also not a core action immediately related to removing the expansion valve, as issues with the expansion valve primarily concern the suction side of the system. Thus, ensuring all suction line manifold valves are closed is the critical step following the removal of the expansion valve.