NEVADA C-21B AIR CONDITIONING
CONTRACTOR EXAM 2026 | PRACTICE EXAM
& ANSWER KEY | NEVADA HVAC
CONTRACTOR LICENSE TEST PREP
NEVADA C-21B AIR CONDITIONING CONTRACTOR EXAM 2026 | PRACTICE EXAM
& ANSWER KEY
DOCUMENT OVERVIEW
• This comprehensive practice exam contains questions designed to prepare you
for the Nevada C-21B Air Conditioning Contractor License Test by reinforcing key
technical knowledge across all exam domains.
• Study strategically by reviewing questions in sections, focusing on rationales to
deepen understanding of concepts, regulations, and practical applications essential
for passing the Nevada contractor certification.
PRACTICE EXAM QUESTIONS
1) QUESTION: What is the primary purpose of a receiver in a refrigeration
system?
A) To measure system pressure accurately
B) To store liquid refrigerant and allow for expansion
C) To filter oil from the refrigerant
D) To regulate compressor speed
E) To separate refrigerant vapor from liquid
✓ CORRECT ANSWER: B) To store liquid refrigerant and allow for expansion
RATIONALE: The receiver (accumulator in some configurations) serves as a storage
tank for liquid refrigerant, allowing the system to accommodate varying refrigerant
quantities during different operating conditions. This prevents liquid slugging and
,ensures proper operation across varying loads. While other components have their
functions, only the receiver provides primary liquid storage and expansion
accommodation.
2) QUESTION: According to EPA regulations, what is the maximum amount of
refrigerant that can be released during normal maintenance of a system?
A) Up to 2 pounds per year
B) Zero intentional release is allowed
C) Up to 5 pounds with documentation
D) Up to 1 pound without reporting
E) Any amount if evacuated to recovery
✓ CORRECT ANSWER: B) Zero intentional release is allowed
RATIONALE: EPA Clean Air Act regulations strictly prohibit venting refrigerants to
the atmosphere during maintenance, repair, or retirement of equipment. All
refrigerants must be recovered using certified recovery equipment. Violations
result in significant fines and license suspension. Intentional venting violates 40 CFR
Part 82 regulations.
3) QUESTION: What does AHRI certification indicate for air conditioning
equipment?
A) The equipment is made in America
B) The equipment meets minimum efficiency and performance standards
C) The equipment has a 10-year warranty
D) The equipment is the most expensive option
E) The equipment never requires maintenance
✓ CORRECT ANSWER: B) The equipment meets minimum efficiency and
performance standards
,RATIONALE: AHRI (Air-Conditioning, Heating, and Refrigeration Institute)
certification demonstrates that equipment has been independently tested and
rated for cooling capacity, heating capacity, and efficiency ratings (SEER, HSPF, EER).
This third-party verification assures compliance with efficiency standards and
provides reliable performance data for contractors and consumers.
4) QUESTION: In a heat pump system operating in heating mode, which
component reverses the refrigerant flow?
A) The expansion device
B) The compressor
C) The reversing valve
D) The check valve
E) The accumulator
✓ CORRECT ANSWER: C) The reversing valve
RATIONALE: The reversing valve is a solenoid-operated device that redirects
refrigerant flow direction in heat pump systems, allowing the indoor and outdoor
coils to switch their functions between heating and cooling modes. The reversing
valve is essential for heat pump operation and allows the system to provide both
heating and cooling from a single outdoor unit.
5) QUESTION: What is the proper evacuation time for a system before
charging with refrigerant?
A) 5 minutes minimum
B) Until 10,000 microns is reached
C) Until 500 microns or lower is reached
D) 30 minutes regardless of size
E) Until no bubbles appear in the sight glass
, ✓ CORRECT ANSWER: C) Until 500 microns or lower is reached
RATIONALE: EPA Section 608 Certification requires evacuation to 500 microns or
lower (some high-efficiency systems require 100 microns or lower) to ensure all
moisture and non-condensable gases are removed. This prevents ice formation at
expansion devices, contamination, and system failures. Micron vacuum
measurement is the industry standard for evacuation verification.
6) QUESTION: Which type of compressor is most commonly used in residential
air conditioning systems?
A) Rotary compressor
B) Screw compressor
C) Scroll compressor
D) Reciprocating compressor
E) Rotary screw compressor
✓ CORRECT ANSWER: C) Scroll compressor
RATIONALE: Scroll compressors have become the standard in modern residential
systems due to their efficiency, quiet operation, reliability, and compact design.
They compress refrigerant using two spiral-shaped scrolls that move together.
Reciprocating compressors were historically common but scroll compressors now
dominate due to superior performance and lower noise levels.
7) QUESTION: What is the function of oil in a refrigeration system?
A) To increase refrigerant density
B) To lubricate the compressor and carry heat
C) To prevent corrosion of copper tubing
D) To improve system cooling capacity
E) To reduce compressor discharge temperature
CONTRACTOR EXAM 2026 | PRACTICE EXAM
& ANSWER KEY | NEVADA HVAC
CONTRACTOR LICENSE TEST PREP
NEVADA C-21B AIR CONDITIONING CONTRACTOR EXAM 2026 | PRACTICE EXAM
& ANSWER KEY
DOCUMENT OVERVIEW
• This comprehensive practice exam contains questions designed to prepare you
for the Nevada C-21B Air Conditioning Contractor License Test by reinforcing key
technical knowledge across all exam domains.
• Study strategically by reviewing questions in sections, focusing on rationales to
deepen understanding of concepts, regulations, and practical applications essential
for passing the Nevada contractor certification.
PRACTICE EXAM QUESTIONS
1) QUESTION: What is the primary purpose of a receiver in a refrigeration
system?
A) To measure system pressure accurately
B) To store liquid refrigerant and allow for expansion
C) To filter oil from the refrigerant
D) To regulate compressor speed
E) To separate refrigerant vapor from liquid
✓ CORRECT ANSWER: B) To store liquid refrigerant and allow for expansion
RATIONALE: The receiver (accumulator in some configurations) serves as a storage
tank for liquid refrigerant, allowing the system to accommodate varying refrigerant
quantities during different operating conditions. This prevents liquid slugging and
,ensures proper operation across varying loads. While other components have their
functions, only the receiver provides primary liquid storage and expansion
accommodation.
2) QUESTION: According to EPA regulations, what is the maximum amount of
refrigerant that can be released during normal maintenance of a system?
A) Up to 2 pounds per year
B) Zero intentional release is allowed
C) Up to 5 pounds with documentation
D) Up to 1 pound without reporting
E) Any amount if evacuated to recovery
✓ CORRECT ANSWER: B) Zero intentional release is allowed
RATIONALE: EPA Clean Air Act regulations strictly prohibit venting refrigerants to
the atmosphere during maintenance, repair, or retirement of equipment. All
refrigerants must be recovered using certified recovery equipment. Violations
result in significant fines and license suspension. Intentional venting violates 40 CFR
Part 82 regulations.
3) QUESTION: What does AHRI certification indicate for air conditioning
equipment?
A) The equipment is made in America
B) The equipment meets minimum efficiency and performance standards
C) The equipment has a 10-year warranty
D) The equipment is the most expensive option
E) The equipment never requires maintenance
✓ CORRECT ANSWER: B) The equipment meets minimum efficiency and
performance standards
,RATIONALE: AHRI (Air-Conditioning, Heating, and Refrigeration Institute)
certification demonstrates that equipment has been independently tested and
rated for cooling capacity, heating capacity, and efficiency ratings (SEER, HSPF, EER).
This third-party verification assures compliance with efficiency standards and
provides reliable performance data for contractors and consumers.
4) QUESTION: In a heat pump system operating in heating mode, which
component reverses the refrigerant flow?
A) The expansion device
B) The compressor
C) The reversing valve
D) The check valve
E) The accumulator
✓ CORRECT ANSWER: C) The reversing valve
RATIONALE: The reversing valve is a solenoid-operated device that redirects
refrigerant flow direction in heat pump systems, allowing the indoor and outdoor
coils to switch their functions between heating and cooling modes. The reversing
valve is essential for heat pump operation and allows the system to provide both
heating and cooling from a single outdoor unit.
5) QUESTION: What is the proper evacuation time for a system before
charging with refrigerant?
A) 5 minutes minimum
B) Until 10,000 microns is reached
C) Until 500 microns or lower is reached
D) 30 minutes regardless of size
E) Until no bubbles appear in the sight glass
, ✓ CORRECT ANSWER: C) Until 500 microns or lower is reached
RATIONALE: EPA Section 608 Certification requires evacuation to 500 microns or
lower (some high-efficiency systems require 100 microns or lower) to ensure all
moisture and non-condensable gases are removed. This prevents ice formation at
expansion devices, contamination, and system failures. Micron vacuum
measurement is the industry standard for evacuation verification.
6) QUESTION: Which type of compressor is most commonly used in residential
air conditioning systems?
A) Rotary compressor
B) Screw compressor
C) Scroll compressor
D) Reciprocating compressor
E) Rotary screw compressor
✓ CORRECT ANSWER: C) Scroll compressor
RATIONALE: Scroll compressors have become the standard in modern residential
systems due to their efficiency, quiet operation, reliability, and compact design.
They compress refrigerant using two spiral-shaped scrolls that move together.
Reciprocating compressors were historically common but scroll compressors now
dominate due to superior performance and lower noise levels.
7) QUESTION: What is the function of oil in a refrigeration system?
A) To increase refrigerant density
B) To lubricate the compressor and carry heat
C) To prevent corrosion of copper tubing
D) To improve system cooling capacity
E) To reduce compressor discharge temperature
