CCP Existing-Building Retro-Cx 3

Question 1

During trend log analysis, you notice that the AHU supply air temperature oscillates ±6°F around setpoint every 8 minutes. This pattern most likely indicates:

Accepted Answer

Hunting caused by aggressive PID control gains

Answer

Rapid, regular oscillation around setpoint is the classic signature of a PID loop that is over-tuned (too high gain or too low integral time).

Question 2

Retro-commissioning of lighting systems most commonly reveals savings opportunities through:

Accepted Answer

Correcting daylighting control setpoints and occupancy sensor coverage gaps

Answer

Miscalibrated daylighting sensors and poorly positioned occupancy sensors are operational faults that prevent lighting controls from delivering their designed energy savings.

Question 3

Which metric is most commonly used to prioritize retro-commissioning measures for implementation?

Accepted Answer

Simple payback period

Answer

Simple payback (cost divided by annual savings) is the standard metric in RCx because it communicates project value to building owners without requiring complex financial modeling.

Question 4

A steam heating system shows persistent condensate backup in multiple traps. The most likely cause identified in RCx is:

Accepted Answer

Failed-closed steam traps blocking condensate drainage

Answer

Failed-closed steam traps block condensate from draining, causing backup that floods heat exchanger coils and reduces heat transfer efficiency.

Question 5

The retro-commissioning scoping phase is primarily used to:

Accepted Answer

Determine the extent of the investigation and develop the project plan

Answer

Scoping defines the systems to be investigated, the data to be collected, and the project schedule and budget before detailed field work begins.

(CCP) Certified Commissioning Professional Practice Test

(CCP) Certified Commissioning Professional Practice Test

CCP Existing-Building Retro-Cx 3