Nevada C-21 Refrigeration & Air
Conditioning Maintenance Contractor
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of a condenser in a refrigeration system?
A. Add heat to the refrigerant
B. Lower refrigerant pressure
C. Reject heat from the refrigerant
D. Increase refrigerant velocity
Rationale: The condenser’s job is to remove heat from the refrigerant so it
can condense back into a liquid.
2. What happens to refrigerant pressure when temperature increases in
a sealed container?
A. It decreases
B. It stays the same
C. It increases
D. It fluctuates randomly
Rationale: Refrigerants follow the pressure–temperature relationship;
higher temperature increases pressure.
,3. Which electrical component controls the operation of a compressor in
most HVAC systems?
A. Capacitor
B. Contactor
C. Transformer
D. Thermistor
Rationale: The contactor opens and closes the circuit supplying power to
the compressor.
4. Which refrigerant is classified as an HFC?
A. R-22
B. R-410A
C. R-12
D. R-717
Rationale: R-410A is an HFC (hydrofluorocarbon) with no chlorine
content.
5. What is subcooling?
A. Refrigerant vapor below saturation temperature
B. Liquid refrigerant cooled below its saturation temperature
C. Increase in vapor temperature
D. Rise in suction pressure
Rationale: Subcooling measures how far liquid refrigerant is cooled below
the condensation point.
6. What tool is commonly used to measure superheat?
A. Tape measure
B. Infrared gun
C. Refrigerant scale
, D. Thermometer plus pressure gauge
Rationale: Superheat is calculated using line temperature and suction
pressure.
7. The EPA 608 certification required for handling refrigerants is
regulated under which U.S. law?
A. Clean Water Act
B. Energy Policy Act
C. Clean Air Act
D. ASHRAE Standard 34
Rationale: Section 608 of the Clean Air Act governs refrigerant handling.
8. What is the purpose of a TXV (Thermostatic Expansion Valve)?
A. Increase compressor efficiency
B. Control refrigerant flow to maintain proper superheat
C. Remove moisture
D. Filter contaminants
Rationale: The TXV meters refrigerant to maintain stable superheat at the
evaporator outlet.
9. What happens when an air filter is severely clogged?
A. More airflow
B. Reduced airflow and possible coil freeze-up
C. Higher superheat
D. Lower static pressure
Rationale: Restricted airflow causes low evaporator temperature, leading to
freeze-ups.
Conditioning Maintenance Contractor
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of a condenser in a refrigeration system?
A. Add heat to the refrigerant
B. Lower refrigerant pressure
C. Reject heat from the refrigerant
D. Increase refrigerant velocity
Rationale: The condenser’s job is to remove heat from the refrigerant so it
can condense back into a liquid.
2. What happens to refrigerant pressure when temperature increases in
a sealed container?
A. It decreases
B. It stays the same
C. It increases
D. It fluctuates randomly
Rationale: Refrigerants follow the pressure–temperature relationship;
higher temperature increases pressure.
,3. Which electrical component controls the operation of a compressor in
most HVAC systems?
A. Capacitor
B. Contactor
C. Transformer
D. Thermistor
Rationale: The contactor opens and closes the circuit supplying power to
the compressor.
4. Which refrigerant is classified as an HFC?
A. R-22
B. R-410A
C. R-12
D. R-717
Rationale: R-410A is an HFC (hydrofluorocarbon) with no chlorine
content.
5. What is subcooling?
A. Refrigerant vapor below saturation temperature
B. Liquid refrigerant cooled below its saturation temperature
C. Increase in vapor temperature
D. Rise in suction pressure
Rationale: Subcooling measures how far liquid refrigerant is cooled below
the condensation point.
6. What tool is commonly used to measure superheat?
A. Tape measure
B. Infrared gun
C. Refrigerant scale
, D. Thermometer plus pressure gauge
Rationale: Superheat is calculated using line temperature and suction
pressure.
7. The EPA 608 certification required for handling refrigerants is
regulated under which U.S. law?
A. Clean Water Act
B. Energy Policy Act
C. Clean Air Act
D. ASHRAE Standard 34
Rationale: Section 608 of the Clean Air Act governs refrigerant handling.
8. What is the purpose of a TXV (Thermostatic Expansion Valve)?
A. Increase compressor efficiency
B. Control refrigerant flow to maintain proper superheat
C. Remove moisture
D. Filter contaminants
Rationale: The TXV meters refrigerant to maintain stable superheat at the
evaporator outlet.
9. What happens when an air filter is severely clogged?
A. More airflow
B. Reduced airflow and possible coil freeze-up
C. Higher superheat
D. Lower static pressure
Rationale: Restricted airflow causes low evaporator temperature, leading to
freeze-ups.
