Which item from the Retro/Re-Commissioning planning phase is explicitly aimed at understanding control logic?

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

Answer: (B)

Understanding how the control logic operates is essential in the planning phase because it directly informs how you verify sequences, interlocks, and setpoints during retro/reh commissioning. By reviewing system operation and control sequences in detail, you map out the exact logic flow, how sensors and actuators interact, and how the system should respond to different conditions. This deep dive ensures you can validate that the installed control logic matches the intended design and meets the owner’s requirements, which is crucial when working with existing systems that may have undocumented or altered logic. The other items are important for broader project scope—gathering information, outlining the overall commissioning plan, or defining procurement—but they do not specifically target understanding the control logic itself.