CO HVAC Controls Contractor Exam – Practice Exam (Questions 1–50)
1. Which of the following is a primary function of a building automation
system (BAS)?
A. Increase manual labor
B. Reduce energy efficiency
C. Optimize HVAC operation
D. Eliminate all maintenance requirements
Rationale: A BAS is designed to control and optimize building systems,
including HVAC, to improve comfort and efficiency.
2. What type of control is commonly used to regulate temperature in an
HVAC system?
A. Pressure control
B. Flow control
C. Temperature control
D. Voltage control
Rationale: Temperature control devices, such as thermostats, sensors,
and controllers, regulate HVAC systems to maintain setpoint
temperatures.
3. In a pneumatic control system, what is the standard supply pressure for
building automation applications?
A. 0–10 psi
B. 15–20 psi
C. 30–35 psi
D. 40–50 psi
Rationale: Pneumatic control systems typically operate with 15–20 psi
to actuate valves and dampers.
4. What is the purpose of a differential pressure sensor in an HVAC
system?
A. Measure room temperature
B. Detect pressure differences across components
C. Control humidity
D. Supply electrical power
Rationale: Differential pressure sensors monitor the pressure
difference across filters, coils, or ducts to ensure proper system
operation.
,5. Which device converts a physical variable, such as temperature, into an
electrical signal for a controller?
A. Actuator
B. Transducer
C. Damper
D. Relay
Rationale: Transducers convert physical measurements (temperature,
pressure, etc.) into electrical signals that a controller can interpret.
6. What is the primary function of a Variable Air Volume (VAV) box?
A. Control humidity only
B. Supply constant air volume
C. Regulate air flow to maintain temperature
D. Filter air exclusively
Rationale: VAV boxes adjust air flow to maintain the desired zone
temperature efficiently.
7. Which type of sensor is most commonly used for detecting room
temperature?
A. Thermocouple
B. Thermistor
C. RTD
D. All of the above
Rationale: Thermocouples, thermistors, and RTDs are all used for
temperature sensing in HVAC applications depending on accuracy and
cost requirements.
8. In Direct Digital Control (DDC) systems, the controller primarily uses:
A. Pneumatic signals
B. Hydraulic signals
C. Digital signals
D. Analog water flow
Rationale: DDC systems utilize digital communication for precise
monitoring and control of HVAC equipment.
9. What is the purpose of a control valve in an HVAC system?
A. Increase noise
B. Regulate fluid flow
C. Supply electrical energy
D. Measure temperature
, Rationale: Control valves modulate the flow of chilled or hot water to
maintain desired temperature in coils.
10. Which of the following is a common fault in VAV systems?
A. Leaking refrigerant
B. Stuck damper
C. Overcharged boiler
D. Faulty furnace filter
Rationale: VAV system issues often arise from mechanical failures like
dampers sticking, causing airflow imbalance.
11. What does PID control stand for in HVAC systems?
A. Pressure, Integration, Delta
B. Proportional, Integral, Derivative
C. Power, Internal, Delay
D. Passive, Immediate, Differential
Rationale: PID controllers continuously calculate an error value and
apply corrections using proportional, integral, and derivative actions.
12. A thermostat setpoint is the:
A. Room humidity
B. Desired temperature for control
C. Fan speed
D. Chiller pressure
Rationale: The setpoint is the target temperature that the HVAC
system aims to maintain.
13. In a chilled water system, which component removes heat from
the water?
A. Boiler
B. Chiller
C. Fan coil
D. Expansion tank
Rationale: Chillers remove heat from water to provide cooling for air
handling units or fan coil units.
14. What is the main purpose of a damper actuator?
A. Measure air velocity
B. Heat the air
C. Move dampers to control air flow
D. Clean filters
1. Which of the following is a primary function of a building automation
system (BAS)?
A. Increase manual labor
B. Reduce energy efficiency
C. Optimize HVAC operation
D. Eliminate all maintenance requirements
Rationale: A BAS is designed to control and optimize building systems,
including HVAC, to improve comfort and efficiency.
2. What type of control is commonly used to regulate temperature in an
HVAC system?
A. Pressure control
B. Flow control
C. Temperature control
D. Voltage control
Rationale: Temperature control devices, such as thermostats, sensors,
and controllers, regulate HVAC systems to maintain setpoint
temperatures.
3. In a pneumatic control system, what is the standard supply pressure for
building automation applications?
A. 0–10 psi
B. 15–20 psi
C. 30–35 psi
D. 40–50 psi
Rationale: Pneumatic control systems typically operate with 15–20 psi
to actuate valves and dampers.
4. What is the purpose of a differential pressure sensor in an HVAC
system?
A. Measure room temperature
B. Detect pressure differences across components
C. Control humidity
D. Supply electrical power
Rationale: Differential pressure sensors monitor the pressure
difference across filters, coils, or ducts to ensure proper system
operation.
,5. Which device converts a physical variable, such as temperature, into an
electrical signal for a controller?
A. Actuator
B. Transducer
C. Damper
D. Relay
Rationale: Transducers convert physical measurements (temperature,
pressure, etc.) into electrical signals that a controller can interpret.
6. What is the primary function of a Variable Air Volume (VAV) box?
A. Control humidity only
B. Supply constant air volume
C. Regulate air flow to maintain temperature
D. Filter air exclusively
Rationale: VAV boxes adjust air flow to maintain the desired zone
temperature efficiently.
7. Which type of sensor is most commonly used for detecting room
temperature?
A. Thermocouple
B. Thermistor
C. RTD
D. All of the above
Rationale: Thermocouples, thermistors, and RTDs are all used for
temperature sensing in HVAC applications depending on accuracy and
cost requirements.
8. In Direct Digital Control (DDC) systems, the controller primarily uses:
A. Pneumatic signals
B. Hydraulic signals
C. Digital signals
D. Analog water flow
Rationale: DDC systems utilize digital communication for precise
monitoring and control of HVAC equipment.
9. What is the purpose of a control valve in an HVAC system?
A. Increase noise
B. Regulate fluid flow
C. Supply electrical energy
D. Measure temperature
, Rationale: Control valves modulate the flow of chilled or hot water to
maintain desired temperature in coils.
10. Which of the following is a common fault in VAV systems?
A. Leaking refrigerant
B. Stuck damper
C. Overcharged boiler
D. Faulty furnace filter
Rationale: VAV system issues often arise from mechanical failures like
dampers sticking, causing airflow imbalance.
11. What does PID control stand for in HVAC systems?
A. Pressure, Integration, Delta
B. Proportional, Integral, Derivative
C. Power, Internal, Delay
D. Passive, Immediate, Differential
Rationale: PID controllers continuously calculate an error value and
apply corrections using proportional, integral, and derivative actions.
12. A thermostat setpoint is the:
A. Room humidity
B. Desired temperature for control
C. Fan speed
D. Chiller pressure
Rationale: The setpoint is the target temperature that the HVAC
system aims to maintain.
13. In a chilled water system, which component removes heat from
the water?
A. Boiler
B. Chiller
C. Fan coil
D. Expansion tank
Rationale: Chillers remove heat from water to provide cooling for air
handling units or fan coil units.
14. What is the main purpose of a damper actuator?
A. Measure air velocity
B. Heat the air
C. Move dampers to control air flow
D. Clean filters
