Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of accomplishing non-major repairs?

Correct Answer: Option D — Bring the part of the system to be opened to 0 psig.

Opening any part of a pressurized refrigerant system requires recovering and venting the section down to 0 psig (atmospheric pressure) to prevent hazardous refrigerant release, oil blowout, and potential injury to engineering personnel.