ASCS EXAM 100% DETAILED VERIFIED CORRECT ANSWERS
2025/2026 STUDY SET
Having a regular HVAC filter replacement plan can help:
A. Protect the system components
B. Double the system's airflow
C. Humidify the airflow
D. Sanitize the system components -ANSWER-A. Protect the system components
According to ACR, the NADCA Standard, properly performed HVAC system cleaning services
should:
A. Eliminate all contamination
B. Restore the internal insulation to an "as new" condition
C. Restore the evaporator coil to its original pressure drop
D. Render the system visibly clean -ANSWER-C. Restore the evaporator coil to its original
pressure drop
Which of the following creates the greatest restriction of airflow?
A. A dirty fan motor
B. A dirty Plenum
C. A dirty Coil
D. A dirty return duct -ANSWER-C. A dirty coil
According to ACR, The NADCA Standard, proper cleaning and maintenance of an HVAC
system:
A. Eliminates odors
B. Adds to the life expectancy of a system
C. Reduces noice pollution
,D. Adds to the value of the HVAC system -ANSWER-B. Adds to the life expectancy of a system
During a commercial site survey, an ASCS should do which of the following to determine
client expectations?
A. Interview the client's employees
B. Ask the client a series of specific questions prior to inspections
C. Perform the inspection without interaction with the client
D. Consult an Indoor Environment Professions (IEP) to determine IAQ -ANSWER-B. Ask the
client a series of specific questions prior to inspections
Dirt streaks around supply diffusers that are NOT cause by a dirty ventilation system are
MOST likely cause by:
A. Slow discharge velocities
B. Elevated relative humidity
C. Dirty room air at the diffuser
D. Thermal stratification around the diffuser -ANSWER-C. Dirty room air at the diffuser
According to ACR, The NADCA Standard, which of the following is the PRIMARY purpose of a
written work plan?
A. Minimizes potential for legal action against the contractor
B. Allows a clear understanding of what work will be performed
C. Ensures compliance with current Occupational Safety and Health Administration (OSHA)
regulations
D. Documents the complete list of materials to be used on the job site -ANSWER-B. Allows a
clear understanding of what work will be performed
A package unit contains which of the following components?
A. Compressor, evaporator coil, condenser, supply fan, and filter
B. Evaporator coil, VAV box, condenser, supply fan, exhaust fan, and filter
C. Compressor, evaporator coil, condenser, supply fan, exhaust fan, and filter
, D. Compressor, evaporator coil, condenser, supply fan, thermostat, and filter -ANSWER-B.
Evaporator coil, VAV box, condenser, supply fan, exhaust fan, and filter
The most common types of fuel consumed in modern residential HVAC systems are:
A. Natural Gas, propane, and oil
B. Electric, propane, and oil
C. Natural gas, methane, and oil
D. Natural gas, Propane, and ethanol -ANSWER-D. Natural gas, Propane, and ethanol
In what sequence is an HVAC system typically cleaned?
A. Supply, air handler
B. Exhaust, air handler, return, supply
C. Return, supply, exhaust, air handler
D. Return, air handler, supply -ANSWER-B. Exhaust, air handler, return, supply
What type of supply fan transfers large volumes of air with a minimal wheel diameter?
A. Backward-inclined fan
B. Forward-curved fan
C. Axial fan
D. Radial Fan -ANSWER-C. Axial fan
According to ACR, The NADCA Standard, coil cleaning should be performed:
A. On the upstream side only
B. On both the upstream and downstream sides
C. On the downstream side only
D. When the system in running -ANSWER-B. On both the upstream and downstream sides
2025/2026 STUDY SET
Having a regular HVAC filter replacement plan can help:
A. Protect the system components
B. Double the system's airflow
C. Humidify the airflow
D. Sanitize the system components -ANSWER-A. Protect the system components
According to ACR, the NADCA Standard, properly performed HVAC system cleaning services
should:
A. Eliminate all contamination
B. Restore the internal insulation to an "as new" condition
C. Restore the evaporator coil to its original pressure drop
D. Render the system visibly clean -ANSWER-C. Restore the evaporator coil to its original
pressure drop
Which of the following creates the greatest restriction of airflow?
A. A dirty fan motor
B. A dirty Plenum
C. A dirty Coil
D. A dirty return duct -ANSWER-C. A dirty coil
According to ACR, The NADCA Standard, proper cleaning and maintenance of an HVAC
system:
A. Eliminates odors
B. Adds to the life expectancy of a system
C. Reduces noice pollution
,D. Adds to the value of the HVAC system -ANSWER-B. Adds to the life expectancy of a system
During a commercial site survey, an ASCS should do which of the following to determine
client expectations?
A. Interview the client's employees
B. Ask the client a series of specific questions prior to inspections
C. Perform the inspection without interaction with the client
D. Consult an Indoor Environment Professions (IEP) to determine IAQ -ANSWER-B. Ask the
client a series of specific questions prior to inspections
Dirt streaks around supply diffusers that are NOT cause by a dirty ventilation system are
MOST likely cause by:
A. Slow discharge velocities
B. Elevated relative humidity
C. Dirty room air at the diffuser
D. Thermal stratification around the diffuser -ANSWER-C. Dirty room air at the diffuser
According to ACR, The NADCA Standard, which of the following is the PRIMARY purpose of a
written work plan?
A. Minimizes potential for legal action against the contractor
B. Allows a clear understanding of what work will be performed
C. Ensures compliance with current Occupational Safety and Health Administration (OSHA)
regulations
D. Documents the complete list of materials to be used on the job site -ANSWER-B. Allows a
clear understanding of what work will be performed
A package unit contains which of the following components?
A. Compressor, evaporator coil, condenser, supply fan, and filter
B. Evaporator coil, VAV box, condenser, supply fan, exhaust fan, and filter
C. Compressor, evaporator coil, condenser, supply fan, exhaust fan, and filter
, D. Compressor, evaporator coil, condenser, supply fan, thermostat, and filter -ANSWER-B.
Evaporator coil, VAV box, condenser, supply fan, exhaust fan, and filter
The most common types of fuel consumed in modern residential HVAC systems are:
A. Natural Gas, propane, and oil
B. Electric, propane, and oil
C. Natural gas, methane, and oil
D. Natural gas, Propane, and ethanol -ANSWER-D. Natural gas, Propane, and ethanol
In what sequence is an HVAC system typically cleaned?
A. Supply, air handler
B. Exhaust, air handler, return, supply
C. Return, supply, exhaust, air handler
D. Return, air handler, supply -ANSWER-B. Exhaust, air handler, return, supply
What type of supply fan transfers large volumes of air with a minimal wheel diameter?
A. Backward-inclined fan
B. Forward-curved fan
C. Axial fan
D. Radial Fan -ANSWER-C. Axial fan
According to ACR, The NADCA Standard, coil cleaning should be performed:
A. On the upstream side only
B. On both the upstream and downstream sides
C. On the downstream side only
D. When the system in running -ANSWER-B. On both the upstream and downstream sides
