In the Retro/Re-Commissioning Planning phase, which activity involves reviewing system operation and control sequences in detail?

• A. Prepare commissioning plan
• B. Review system operation and control sequences in detail
• C. Carry out a survey to gather needed information
• D. The owner selects the commissioning authority

Answer: (B)

Understanding exactly how the system should operate and how its control sequences are supposed to behave is the focus here. In retro/re-commissioning planning, the goal is to verify that the existing control logic, sequencing, setpoints, interlocks, and alarms are understood and documented so you can create accurate test procedures and acceptance criteria. This detailed review anchors the rest of the work, because without a precise picture of intended operation you can’t effectively validate performance or diagnose issues. Other activities—setting up the overall plan, collecting information, or selecting the commissioning authority—serve different planning or procurement purposes rather than the in-depth analysis of operation and control logic that this step requires.