BOC HVAC Systems Operation &
Maintenance Assessment Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary function of an HVAC system in a building?
A. To generate electrical power
B. To provide heating, ventilation, and air conditioning for indoor
comfort
C. To supply domestic hot water only
D. To control lighting levels
Correct Answer: B
HVAC systems are designed to regulate indoor environmental
conditions by providing heating, cooling, and ventilation to maintain
occupant comfort and acceptable air quality.
2. Which component is responsible for removing heat from a space in a
vapor-compression refrigeration cycle?
, A. Expansion valve
B. Evaporator
C. Compressor
D. Condenser
Correct Answer: B
The evaporator absorbs heat from the indoor air as the refrigerant
evaporates, thereby cooling the space.
3. What is the role of the compressor in an HVAC system?
A. To reduce refrigerant pressure
B. To expand refrigerant into a gas
C. To circulate and pressurize refrigerant
D. To remove moisture from air
Correct Answer: C
The compressor increases refrigerant pressure and circulates it
through the system to enable heat transfer.
4. Which device controls refrigerant flow into the evaporator?
A. Thermostat
B. Expansion valve
C. Fan motor
D. Air handler
Correct Answer: B
The expansion valve meters refrigerant flow and reduces its pressure
before entering the evaporator.
,5. What is the purpose of a thermostat in HVAC systems?
A. To compress refrigerant
B. To measure humidity only
C. To regulate temperature by controlling system operation
D. To filter air contaminants
Correct Answer: C
A thermostat senses indoor temperature and signals HVAC
equipment to turn on or off to maintain setpoints.
6. Which filter type is most commonly used in commercial HVAC
systems?
A. HEPA filters only
B. Fiberglass or pleated air filters
C. Carbon fiber mesh
D. Metal mesh only
Correct Answer: B
Fiberglass and pleated filters are widely used due to their balance of
efficiency and airflow resistance.
7. What is the main purpose of HVAC ventilation?
A. Increase refrigerant pressure
B. Remove indoor air pollutants and supply fresh air
C. Reduce electrical consumption
D. Heat refrigerant gas
Correct Answer: B
, Ventilation improves indoor air quality by diluting contaminants and
introducing fresh outdoor air.
8. What does a cooling tower primarily do?
A. Compress refrigerant
B. Reject heat from condenser water to the atmosphere
C. Filter air in ducts
D. Heat incoming air
Correct Answer: B
Cooling towers remove heat from condenser water through
evaporation and heat exchange with outdoor air.
9. Which refrigerant property is most important for HVAC performance?
A. Color
B. Odor
C. Boiling point
D. Electrical conductivity
Correct Answer: C
The boiling point determines how effectively refrigerant can absorb
and release heat in phase changes.
10. What is a common symptom of low refrigerant charge?
A. Increased cooling capacity
B. Frost on evaporator coil and reduced cooling
C. Higher airflow
D. Increased humidity removal
Maintenance Assessment Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary function of an HVAC system in a building?
A. To generate electrical power
B. To provide heating, ventilation, and air conditioning for indoor
comfort
C. To supply domestic hot water only
D. To control lighting levels
Correct Answer: B
HVAC systems are designed to regulate indoor environmental
conditions by providing heating, cooling, and ventilation to maintain
occupant comfort and acceptable air quality.
2. Which component is responsible for removing heat from a space in a
vapor-compression refrigeration cycle?
, A. Expansion valve
B. Evaporator
C. Compressor
D. Condenser
Correct Answer: B
The evaporator absorbs heat from the indoor air as the refrigerant
evaporates, thereby cooling the space.
3. What is the role of the compressor in an HVAC system?
A. To reduce refrigerant pressure
B. To expand refrigerant into a gas
C. To circulate and pressurize refrigerant
D. To remove moisture from air
Correct Answer: C
The compressor increases refrigerant pressure and circulates it
through the system to enable heat transfer.
4. Which device controls refrigerant flow into the evaporator?
A. Thermostat
B. Expansion valve
C. Fan motor
D. Air handler
Correct Answer: B
The expansion valve meters refrigerant flow and reduces its pressure
before entering the evaporator.
,5. What is the purpose of a thermostat in HVAC systems?
A. To compress refrigerant
B. To measure humidity only
C. To regulate temperature by controlling system operation
D. To filter air contaminants
Correct Answer: C
A thermostat senses indoor temperature and signals HVAC
equipment to turn on or off to maintain setpoints.
6. Which filter type is most commonly used in commercial HVAC
systems?
A. HEPA filters only
B. Fiberglass or pleated air filters
C. Carbon fiber mesh
D. Metal mesh only
Correct Answer: B
Fiberglass and pleated filters are widely used due to their balance of
efficiency and airflow resistance.
7. What is the main purpose of HVAC ventilation?
A. Increase refrigerant pressure
B. Remove indoor air pollutants and supply fresh air
C. Reduce electrical consumption
D. Heat refrigerant gas
Correct Answer: B
, Ventilation improves indoor air quality by diluting contaminants and
introducing fresh outdoor air.
8. What does a cooling tower primarily do?
A. Compress refrigerant
B. Reject heat from condenser water to the atmosphere
C. Filter air in ducts
D. Heat incoming air
Correct Answer: B
Cooling towers remove heat from condenser water through
evaporation and heat exchange with outdoor air.
9. Which refrigerant property is most important for HVAC performance?
A. Color
B. Odor
C. Boiling point
D. Electrical conductivity
Correct Answer: C
The boiling point determines how effectively refrigerant can absorb
and release heat in phase changes.
10. What is a common symptom of low refrigerant charge?
A. Increased cooling capacity
B. Frost on evaporator coil and reduced cooling
C. Higher airflow
D. Increased humidity removal
