Coast Guard Exams
Question 217General Subjects - 1st Asst/Chief70% to pass

Referring to the illustrated single zone HVAC system diagram, what statement is true concerning the damper controls? Illustration GS-RA-09

AI Explanation
The correct answer is B. The exhaust and outside air dampers are normally closed, and the recirculation damper is normally open. This allows the system to primarily recirculate air within the building, minimizing the need for outside air. All three dampers are controlled by a single pilot air signal, which means they move in unison based on the control system's needs. The other options are incorrect because they do not accurately describe the normal positions of the dampers or the control method. Option A has the dampers in the wrong normal positions, and option C and D have each damper controlled by its own pilot air signal, which is not the case in this single zone HVAC system diagram.