AR BAS Building Automation Contractor
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a building automation system (BAS)?
A. To replace all mechanical equipment in a building
B. To eliminate the need for building maintenance personnel
C. To monitor and control building systems for efficient and reliable
operation
D. To provide electrical power to all building equipment
Rationale: A BAS integrates monitoring and control of systems such as
HVAC, lighting, and selected electrical or safety-related equipment. It
helps maintain occupant comfort, improve energy efficiency, identify
equipment problems, and coordinate building operations. It does not
,replace the mechanical equipment itself or eliminate the need for
maintenance personnel.
2. Which component of a BAS receives sensor information, executes
control logic, and sends commands to controlled equipment?
A. Circuit breaker
B. Direct digital controller (DDC)
C. Manual disconnect switch
D. Transformer
Rationale: A direct digital controller receives inputs from sensors and
other devices, processes those inputs using programmed control
sequences, and sends outputs to actuators, relays, or other
equipment. Circuit breakers provide overcurrent protection,
disconnect switches isolate electrical equipment, and transformers
change voltage levels.
3. What is the primary function of a temperature sensor in an HVAC
control system?
A. To increase the electrical voltage supplied to a motor
B. To regulate refrigerant pressure directly
,C. To measure temperature and provide information for control
decisions
D. To open a circuit breaker during an overload
Rationale: A temperature sensor measures the temperature of air,
water, or another medium and communicates the measurement to a
controller. The controller compares the measured value with a desired
setpoint and determines whether heating, cooling, or another control
action is needed.
4. What does the term “setpoint” mean in a building automation
system?
A. The maximum electrical current of a controller
B. The physical location of a temperature sensor
C. The desired value that a control system attempts to maintain
D. The communication address of a field device
Rationale: A setpoint is the target value for a controlled variable, such
as room temperature, duct static pressure, or chilled-water
temperature. The controller uses feedback from sensors to determine
whether the system should adjust its outputs to move the measured
condition toward that target.
, 5. Which device converts a controller’s electrical command into
mechanical movement to position a damper?
A. Thermistor
B. Differential pressure sensor
C. Damper actuator
D. Current transformer
Rationale: A damper actuator converts an electrical, pneumatic, or
other control signal into mechanical motion that opens, closes, or
modulates a damper. Actuator sizing, torque, stroke, and control-
signal compatibility must be appropriate for the damper and its
operating conditions.
6. What is the main function of a variable frequency drive (VFD) in an
HVAC application?
A. To measure room humidity
B. To convert analog sensor readings into digital values
C. To vary motor speed by adjusting the frequency supplied to the
motor
D. To provide fire alarm notification
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a building automation system (BAS)?
A. To replace all mechanical equipment in a building
B. To eliminate the need for building maintenance personnel
C. To monitor and control building systems for efficient and reliable
operation
D. To provide electrical power to all building equipment
Rationale: A BAS integrates monitoring and control of systems such as
HVAC, lighting, and selected electrical or safety-related equipment. It
helps maintain occupant comfort, improve energy efficiency, identify
equipment problems, and coordinate building operations. It does not
,replace the mechanical equipment itself or eliminate the need for
maintenance personnel.
2. Which component of a BAS receives sensor information, executes
control logic, and sends commands to controlled equipment?
A. Circuit breaker
B. Direct digital controller (DDC)
C. Manual disconnect switch
D. Transformer
Rationale: A direct digital controller receives inputs from sensors and
other devices, processes those inputs using programmed control
sequences, and sends outputs to actuators, relays, or other
equipment. Circuit breakers provide overcurrent protection,
disconnect switches isolate electrical equipment, and transformers
change voltage levels.
3. What is the primary function of a temperature sensor in an HVAC
control system?
A. To increase the electrical voltage supplied to a motor
B. To regulate refrigerant pressure directly
,C. To measure temperature and provide information for control
decisions
D. To open a circuit breaker during an overload
Rationale: A temperature sensor measures the temperature of air,
water, or another medium and communicates the measurement to a
controller. The controller compares the measured value with a desired
setpoint and determines whether heating, cooling, or another control
action is needed.
4. What does the term “setpoint” mean in a building automation
system?
A. The maximum electrical current of a controller
B. The physical location of a temperature sensor
C. The desired value that a control system attempts to maintain
D. The communication address of a field device
Rationale: A setpoint is the target value for a controlled variable, such
as room temperature, duct static pressure, or chilled-water
temperature. The controller uses feedback from sensors to determine
whether the system should adjust its outputs to move the measured
condition toward that target.
, 5. Which device converts a controller’s electrical command into
mechanical movement to position a damper?
A. Thermistor
B. Differential pressure sensor
C. Damper actuator
D. Current transformer
Rationale: A damper actuator converts an electrical, pneumatic, or
other control signal into mechanical motion that opens, closes, or
modulates a damper. Actuator sizing, torque, stroke, and control-
signal compatibility must be appropriate for the damper and its
operating conditions.
6. What is the main function of a variable frequency drive (VFD) in an
HVAC application?
A. To measure room humidity
B. To convert analog sensor readings into digital values
C. To vary motor speed by adjusting the frequency supplied to the
motor
D. To provide fire alarm notification
