CCP Existing-Building Retro-Cx 5

Question 1

A retro-commissioning investigation finds that supply air static pressure setpoint is 1.5 in. w.g. and never resets downward even at low load. The recommended measure is:

Accepted Answer

Implement supply air static pressure reset based on VAV box damper positions

Answer

Static pressure reset—reducing setpoint when all VAV boxes have adequate flow—is a proven RCx measure that cuts fan energy significantly at partial load.

Question 2

During RCx, it is discovered that a building's controls sequence calls for chilled water supply temperature reset, but the reset has been disabled. The most likely reason found in O&M interviews is:

Accepted Answer

Operators disabled it after occupant complaints about inadequate cooling during one summer

Answer

Operators often disable energy-saving sequences after a comfort complaint, and the sequence never gets re-enabled—a common RCx finding that represents recoverable savings.

Question 3

Which of the following is NOT typically part of the RCx investigation phase?

Accepted Answer

Installing permanent submetering equipment throughout the building

Answer

Permanent submetering installation is a capital project, not a standard RCx investigation activity; RCx uses existing meters, portable loggers, and BAS trends.

Question 4

A large office building's chiller plant is found to run two equally sized chillers at 40% load each rather than one chiller at 80% load. This is most likely due to:

Accepted Answer

A control sequence that lacks a chiller staging algorithm based on load

Answer

Without a proper staging algorithm, chiller plants often run multiple machines at low efficiency rather than consolidating load on fewer chillers operating near their peak efficiency.

Question 5

In retro-commissioning, the term 'deferred maintenance' refers to:

Accepted Answer

Maintenance tasks that have been postponed and are now causing performance degradation

Answer

Deferred maintenance consists of overdue upkeep tasks—dirty coils, worn belts, failed actuators—that directly reduce system performance and are commonly uncovered during RCx.

(CCP) Certified Commissioning Professional Practice Test

(CCP) Certified Commissioning Professional Practice Test

CCP Existing-Building Retro-Cx 5