After recovering liquid refrigerant from a low pressure chiller, what must a technician do next?

After recovering liquid refrigerant from a low pressure chiller, the technician's next step should be to recover the refrigerant vapor. This is important because it ensures that all refrigerant is safely removed from the system, minimizing the risk of refrigerant leaks into the atmosphere and also preparing the system for maintenance or repair.

Recovering vapor after the liquid refrigerant has been extracted is critical for the complete recovery process. If any vapor remains in the system, it could lead to increased pressure, which can complicate repairs or even endanger safety. Moreover, capturing the vapor helps in achieving a lower pressure within the system, allowing for a more thorough maintenance process.

The other actions listed, such as inspecting the compressor, charging the system, or conducting a leak test, are relevant at different stages but do not follow directly after liquid recovery. Each of those actions serves a specific purpose in the maintenance or servicing process but should come after ensuring that all refrigerant, in both liquid and vapor form, has been effectively recovered.