City of Omaha ACAD (Air
Conditioning/Air Distribution)
Journeyman Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
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1.A commercial air conditioning system has a supply air temperature of 55°F
and a return air temperature of 75°F. What is the primary purpose of this
temperature difference in an air distribution system?
A. To increase refrigerant pressure
B. To provide sensible cooling capacity by removing heat from the
conditioned space
C. To increase compressor oil circulation
D. To reduce electrical resistance in motors
Answer: B. To provide sensible cooling capacity by removing heat from the
conditioned space
The supply-to-return air temperature difference represents the sensible
heat removal process. The cooler supply air absorbs heat from the
occupied space as it circulates, reducing the room temperature to the
desired level.
2. In an air conditioning system, the air handler blower motor fails to
operate while the compressor continues running. What is the most
likely immediate consequence?
,A. Increased airflow across the evaporator coil
B. Reduced refrigerant superheat
C. Evaporator coil icing due to insufficient airflow
D. Increased condenser airflow
Answer: C. Evaporator coil icing due to insufficient airflow
When airflow across the evaporator coil is restricted, the coil temperature
drops excessively, causing moisture to freeze on the coil surface and
reducing system performance.
3. The primary function of a thermostatic expansion valve (TXV) in a
refrigeration system is to:
A. Control refrigerant flow into the evaporator based on superheat
B. Increase compressor discharge pressure
C. Remove moisture from refrigerant
D. Control condenser fan speed
Answer: A. Control refrigerant flow into the evaporator based on
superheat
A TXV regulates refrigerant entering the evaporator to maintain proper
superheat, preventing liquid refrigerant from returning to the compressor
while maximizing coil performance.
4. What is the purpose of a return air duct in an HVAC system?
A. Deliver conditioned air directly into occupied spaces
B. Remove combustion gases
C. Carry air from the conditioned space back to the air-handling unit
D. Increase refrigerant velocity
Answer: C. Carry air from the conditioned space back to the air-handling
unit
,Return ducts collect room air and transport it back to the HVAC equipment
where it can be filtered, conditioned, and recirculated.
5. A dirty air filter in an air conditioning system will most commonly
cause:
A. Increased airflow and lower operating pressure
B. Reduced airflow and possible evaporator freezing
C. Higher compressor efficiency
D. Increased condenser capacity
Answer: B. Reduced airflow and possible evaporator freezing
A clogged filter restricts airflow, reducing heat transfer across the
evaporator coil and potentially causing the coil temperature to fall below
freezing.
6. The purpose of a duct system balancing procedure is to:
A. Increase refrigerant charge
B. Ensure proper airflow distribution throughout the building
C. Reduce compressor lubrication
D. Eliminate the need for filters
Answer: B. Ensure proper airflow distribution throughout the building
Air balancing adjusts dampers and system components so each space
receives the designed amount of conditioned air for comfort and
performance.
7. What instrument is commonly used to measure static pressure in an
HVAC duct system?
A. Micrometer
B. Manometer
C. Tachometer
D. Megohmmeter
, Answer: B. Manometer
A manometer measures pressure differences within duct systems and is
used for diagnosing airflow problems and verifying system operation.
8. The sensible heat ratio (SHR) represents:
A. The percentage of total heat load that is sensible heat
B. The amount of refrigerant in the system
C. The airflow resistance of a duct
D. The electrical efficiency of a motor
Answer: A. The percentage of total heat load that is sensible heat
SHR compares sensible cooling requirements to total cooling requirements,
helping determine proper equipment selection and performance.
9. A properly designed return air system should:
A. Create excessive negative pressure
B. Provide adequate airflow back to the air handler
C. Eliminate all outdoor air intake
D. Increase duct leakage
Answer: B. Provide adequate airflow back to the air handler
Proper return airflow is essential for maintaining balanced pressure,
comfort, and efficient HVAC operation.
10. What is the primary purpose of an economizer on a commercial
HVAC unit?
A. Increase compressor speed
B. Use outdoor air for free cooling when conditions allow
C. Increase refrigerant pressure
D. Reduce condenser airflow
Answer: B. Use outdoor air for free cooling when conditions allow
Conditioning/Air Distribution)
Journeyman Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
Download Pdf
1.A commercial air conditioning system has a supply air temperature of 55°F
and a return air temperature of 75°F. What is the primary purpose of this
temperature difference in an air distribution system?
A. To increase refrigerant pressure
B. To provide sensible cooling capacity by removing heat from the
conditioned space
C. To increase compressor oil circulation
D. To reduce electrical resistance in motors
Answer: B. To provide sensible cooling capacity by removing heat from the
conditioned space
The supply-to-return air temperature difference represents the sensible
heat removal process. The cooler supply air absorbs heat from the
occupied space as it circulates, reducing the room temperature to the
desired level.
2. In an air conditioning system, the air handler blower motor fails to
operate while the compressor continues running. What is the most
likely immediate consequence?
,A. Increased airflow across the evaporator coil
B. Reduced refrigerant superheat
C. Evaporator coil icing due to insufficient airflow
D. Increased condenser airflow
Answer: C. Evaporator coil icing due to insufficient airflow
When airflow across the evaporator coil is restricted, the coil temperature
drops excessively, causing moisture to freeze on the coil surface and
reducing system performance.
3. The primary function of a thermostatic expansion valve (TXV) in a
refrigeration system is to:
A. Control refrigerant flow into the evaporator based on superheat
B. Increase compressor discharge pressure
C. Remove moisture from refrigerant
D. Control condenser fan speed
Answer: A. Control refrigerant flow into the evaporator based on
superheat
A TXV regulates refrigerant entering the evaporator to maintain proper
superheat, preventing liquid refrigerant from returning to the compressor
while maximizing coil performance.
4. What is the purpose of a return air duct in an HVAC system?
A. Deliver conditioned air directly into occupied spaces
B. Remove combustion gases
C. Carry air from the conditioned space back to the air-handling unit
D. Increase refrigerant velocity
Answer: C. Carry air from the conditioned space back to the air-handling
unit
,Return ducts collect room air and transport it back to the HVAC equipment
where it can be filtered, conditioned, and recirculated.
5. A dirty air filter in an air conditioning system will most commonly
cause:
A. Increased airflow and lower operating pressure
B. Reduced airflow and possible evaporator freezing
C. Higher compressor efficiency
D. Increased condenser capacity
Answer: B. Reduced airflow and possible evaporator freezing
A clogged filter restricts airflow, reducing heat transfer across the
evaporator coil and potentially causing the coil temperature to fall below
freezing.
6. The purpose of a duct system balancing procedure is to:
A. Increase refrigerant charge
B. Ensure proper airflow distribution throughout the building
C. Reduce compressor lubrication
D. Eliminate the need for filters
Answer: B. Ensure proper airflow distribution throughout the building
Air balancing adjusts dampers and system components so each space
receives the designed amount of conditioned air for comfort and
performance.
7. What instrument is commonly used to measure static pressure in an
HVAC duct system?
A. Micrometer
B. Manometer
C. Tachometer
D. Megohmmeter
, Answer: B. Manometer
A manometer measures pressure differences within duct systems and is
used for diagnosing airflow problems and verifying system operation.
8. The sensible heat ratio (SHR) represents:
A. The percentage of total heat load that is sensible heat
B. The amount of refrigerant in the system
C. The airflow resistance of a duct
D. The electrical efficiency of a motor
Answer: A. The percentage of total heat load that is sensible heat
SHR compares sensible cooling requirements to total cooling requirements,
helping determine proper equipment selection and performance.
9. A properly designed return air system should:
A. Create excessive negative pressure
B. Provide adequate airflow back to the air handler
C. Eliminate all outdoor air intake
D. Increase duct leakage
Answer: B. Provide adequate airflow back to the air handler
Proper return airflow is essential for maintaining balanced pressure,
comfort, and efficient HVAC operation.
10. What is the primary purpose of an economizer on a commercial
HVAC unit?
A. Increase compressor speed
B. Use outdoor air for free cooling when conditions allow
C. Increase refrigerant pressure
D. Reduce condenser airflow
Answer: B. Use outdoor air for free cooling when conditions allow
