City of Omaha ACAD (Air
Conditioning/Air Distribution) Master
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
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1. A licensed City of Omaha Master ACAD contractor is responsible for
installing a commercial air distribution system. Which of the following
best describes the primary purpose of an air distribution system?
A. To generate refrigerant pressure inside the compressor
B. To move conditioned air throughout a building while maintaining comfort
and air quality
C. To increase electrical voltage supplied to HVAC equipment
D. To remove all humidity without using cooling equipment
Answer: B. To move conditioned air throughout a building while
maintaining comfort and air quality
An air distribution system is designed to deliver conditioned air to occupied
spaces, maintain temperature control, provide ventilation, and support
indoor air quality. It includes components such as ducts, grilles, registers,
diffusers, fans, and dampers.
2. A contractor is sizing a supply air duct for a commercial HVAC system.
Which factor has the greatest impact on the required duct size?
,A. Paint color of the duct exterior
B. Required airflow volume and acceptable pressure loss
C. Brand name of the thermostat
D. Refrigerant type only
Answer: B. Required airflow volume and acceptable pressure loss
Duct sizing depends primarily on airflow requirements, velocity limits,
friction losses, and system pressure characteristics. Proper sizing ensures
adequate air delivery without excessive noise or energy consumption.
3. In an air conditioning system, the evaporator coil performs which
function?
A. Rejects heat to outdoor air
B. Compresses refrigerant vapor
C. Absorbs heat from indoor air
D. Controls electrical voltage
Answer: C. Absorbs heat from indoor air
The evaporator coil absorbs heat from the conditioned space as refrigerant
changes from a low-pressure liquid mixture into vapor. This process cools
and dehumidifies the air passing over the coil.
4. A technician measures static pressure in an HVAC duct system. What
does static pressure indicate?
A. Refrigerant temperature only
B. Resistance to airflow within the system
C. Electrical resistance in motors
D. Outdoor humidity level
Answer: B. Resistance to airflow within the system
,Static pressure measures the resistance that air encounters as it moves
through ducts, filters, coils, and other components. Excessive static
pressure can reduce airflow and damage equipment.
5. When installing flexible ductwork, which practice is most important
for maintaining system efficiency?
A. Allowing excessive sagging between supports
B. Keeping bends smooth and minimizing restrictions
C. Leaving insulation removed for easier inspection
D. Installing ducts without sealing connections
Answer: B. Keeping bends smooth and minimizing restrictions
Flexible duct must be properly supported, stretched tight, and installed
with smooth transitions because compression, sharp bends, and sagging
increase airflow resistance and energy losses.
6. What is the purpose of a thermostat in a typical HVAC control system?
A. To increase compressor horsepower
B. To sense space conditions and control equipment operation
C. To filter contaminants from refrigerant
D. To regulate duct insulation thickness
Answer: B. To sense space conditions and control equipment operation
A thermostat monitors temperature conditions and signals heating or
cooling equipment to operate as needed to maintain the desired indoor
environment.
7. A return air duct system that is too small will most likely cause which
problem?
A. Increased airflow and improved efficiency
B. Reduced static pressure
, C. Poor airflow and increased system strain
D. Lower electrical consumption
Answer: C. Poor airflow and increased system strain
An undersized return duct restricts air movement, increasing static
pressure and reducing the amount of air reaching the equipment and
conditioned spaces.
8. Which instrument is commonly used to measure air velocity in HVAC
systems?
A. Micrometer
B. Anemometer
C. Ohmmeter
D. Manifold gauge
Answer: B. Anemometer
An anemometer measures air velocity and is commonly used during
airflow testing and balancing procedures to verify proper system
performance.
9. The main purpose of a filter in an air handling system is to:
A. Increase refrigerant pressure
B. Remove airborne particles from circulating air
C. Reduce compressor temperature
D. Increase duct velocity
Answer: B. Remove airborne particles from circulating air
Air filters capture dust, debris, and other contaminants before air is
circulated through the building and HVAC equipment.
10. A properly designed HVAC system should maintain which
balance between supply and return air?
Conditioning/Air Distribution) Master
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
.
1. A licensed City of Omaha Master ACAD contractor is responsible for
installing a commercial air distribution system. Which of the following
best describes the primary purpose of an air distribution system?
A. To generate refrigerant pressure inside the compressor
B. To move conditioned air throughout a building while maintaining comfort
and air quality
C. To increase electrical voltage supplied to HVAC equipment
D. To remove all humidity without using cooling equipment
Answer: B. To move conditioned air throughout a building while
maintaining comfort and air quality
An air distribution system is designed to deliver conditioned air to occupied
spaces, maintain temperature control, provide ventilation, and support
indoor air quality. It includes components such as ducts, grilles, registers,
diffusers, fans, and dampers.
2. A contractor is sizing a supply air duct for a commercial HVAC system.
Which factor has the greatest impact on the required duct size?
,A. Paint color of the duct exterior
B. Required airflow volume and acceptable pressure loss
C. Brand name of the thermostat
D. Refrigerant type only
Answer: B. Required airflow volume and acceptable pressure loss
Duct sizing depends primarily on airflow requirements, velocity limits,
friction losses, and system pressure characteristics. Proper sizing ensures
adequate air delivery without excessive noise or energy consumption.
3. In an air conditioning system, the evaporator coil performs which
function?
A. Rejects heat to outdoor air
B. Compresses refrigerant vapor
C. Absorbs heat from indoor air
D. Controls electrical voltage
Answer: C. Absorbs heat from indoor air
The evaporator coil absorbs heat from the conditioned space as refrigerant
changes from a low-pressure liquid mixture into vapor. This process cools
and dehumidifies the air passing over the coil.
4. A technician measures static pressure in an HVAC duct system. What
does static pressure indicate?
A. Refrigerant temperature only
B. Resistance to airflow within the system
C. Electrical resistance in motors
D. Outdoor humidity level
Answer: B. Resistance to airflow within the system
,Static pressure measures the resistance that air encounters as it moves
through ducts, filters, coils, and other components. Excessive static
pressure can reduce airflow and damage equipment.
5. When installing flexible ductwork, which practice is most important
for maintaining system efficiency?
A. Allowing excessive sagging between supports
B. Keeping bends smooth and minimizing restrictions
C. Leaving insulation removed for easier inspection
D. Installing ducts without sealing connections
Answer: B. Keeping bends smooth and minimizing restrictions
Flexible duct must be properly supported, stretched tight, and installed
with smooth transitions because compression, sharp bends, and sagging
increase airflow resistance and energy losses.
6. What is the purpose of a thermostat in a typical HVAC control system?
A. To increase compressor horsepower
B. To sense space conditions and control equipment operation
C. To filter contaminants from refrigerant
D. To regulate duct insulation thickness
Answer: B. To sense space conditions and control equipment operation
A thermostat monitors temperature conditions and signals heating or
cooling equipment to operate as needed to maintain the desired indoor
environment.
7. A return air duct system that is too small will most likely cause which
problem?
A. Increased airflow and improved efficiency
B. Reduced static pressure
, C. Poor airflow and increased system strain
D. Lower electrical consumption
Answer: C. Poor airflow and increased system strain
An undersized return duct restricts air movement, increasing static
pressure and reducing the amount of air reaching the equipment and
conditioned spaces.
8. Which instrument is commonly used to measure air velocity in HVAC
systems?
A. Micrometer
B. Anemometer
C. Ohmmeter
D. Manifold gauge
Answer: B. Anemometer
An anemometer measures air velocity and is commonly used during
airflow testing and balancing procedures to verify proper system
performance.
9. The main purpose of a filter in an air handling system is to:
A. Increase refrigerant pressure
B. Remove airborne particles from circulating air
C. Reduce compressor temperature
D. Increase duct velocity
Answer: B. Remove airborne particles from circulating air
Air filters capture dust, debris, and other contaminants before air is
circulated through the building and HVAC equipment.
10. A properly designed HVAC system should maintain which
balance between supply and return air?
