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100+ Free NV C-21D Refrigeration and AC Maintenance Practice Questions

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2026 Statistics

Key Facts: NV C-21D Refrigeration and AC Maintenance Exam

60 Q

Official Exam Questions

PSI Nevada Contractor CIB updated 3/25/2026

70%

Passing Score

PSI Nevada Contractor CIB updated 3/25/2026

2 hours

Time Allowed

PSI Nevada Contractor CIB updated 3/25/2026

USD 95

PSI Exam Fee (one portion)

PSI Nevada Contractor CIB updated 3/25/2026

Open Book

Book Policy

PSI Nevada Contractor CIB updated 3/25/2026

Nevada C-21D Refrigeration and Air Conditioning Maintenance Contractor Examination is the official NSCB/PSI open book exam: 60 questions, 70% (42 of 60 points), 2 hours, USD 95 (bulletin 270, updated 3/25/2026). Official delivery: English.

Sample NV C-21D Refrigeration and AC Maintenance Practice Questions

Try these sample questions to test your NV C-21D Refrigeration and AC Maintenance exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under NAC 624.380, which task is within Nevada C-21D Refrigeration and Air Conditioning Maintenance scope?
A.Replace the complete remote condenser assembly on a split refrigeration system
B.Replace an existing air handler with a larger-capacity unit
C.Redesign a rooftop unit to a different refrigerant and new coil circuiting
D.Replace a failed compressor, motor, relay, or coil on an existing air-conditioning unit
Explanation: NAC 624.380(3)(d) authorizes C-21D work as repair and replacement of parts of existing air-conditioning and refrigeration units, including compressors, motors, relays, coils, heat exchangers, and other appurtenances. The same paragraph excludes complete condenser assemblies on remote systems, air handlers, and any work that may alter the design of an existing system.
2A C-21D contractor is asked to swap the entire outdoor remote condenser assembly on an existing split refrigeration rack. What is the correct scope decision?
A.Proceed; any outdoor work is C-21D maintenance
B.Decline the complete assembly replacement; C-21D may replace condenser coils, fans, motors, and relays, but not the complete remote condenser assembly
C.Proceed if the new assembly has the same footprint
D.Proceed if the owner signs a design-change waiver
Explanation: NAC 624.380(3)(d) lets C-21D replace parts of existing units, including coils and motors, but it expressly bars replacement of complete condenser assemblies on remote systems. Matching footprint or an owner waiver does not expand the classification. That work belongs to a broader C-21 or C-21A/C-21B license.
3Which existing-system repair is allowed under C-21D without altering system design?
A.Replace the indoor air handler and resize the supply duct
B.Convert a capillary-tube system to a custom-engineered EEV rack
C.Install a new split system where none exists
D.Replace a leaking evaporator coil with a same-circuit, same-capacity coil
Explanation: Replacing a coil (a listed C-21D part) with a like-for-like heat exchanger keeps the existing design. Air-handler replacement, metering-scheme redesign, and new-system installation are outside C-21D. UMC 2018 still requires the replacement part to be listed for the refrigerant and pressures of the existing system.
4What are the four essential components of the vapor-compression refrigeration cycle on an existing C-21D unit?
A.Compressor, reversing valve, receiver, and accumulator
B.Compressor, condenser, metering device, and evaporator
C.Condenser, cooling tower, pump, and expansion tank
D.Filter-drier, sight glass, service valve, and crankcase heater
Explanation: Heat is absorbed in the evaporator, compressed, rejected in the condenser, and dropped in pressure at the metering device. Receivers, accumulators, driers, and reversing valves are accessories. A C-21D technician must be able to identify and replace those four core parts without changing the system design.
5On an operating air-conditioning unit, where does refrigerant absorb heat from the conditioned air?
A.The condenser coil
B.The compressor discharge muffler
C.The evaporator coil
D.The liquid-line filter-drier
Explanation: Low-pressure liquid refrigerant boils in the evaporator and absorbs latent heat from the air (or secondary fluid) passing over the coil. The condenser rejects that heat outdoors. C-21D coil replacement must restore that heat-absorption surface without changing circuiting or capacity.
6What is the primary function of the condenser on an existing air-cooled refrigeration unit?
A.To boil liquid refrigerant and absorb space heat
B.To reject heat so high-pressure vapor condenses to liquid
C.To drop refrigerant pressure to evaporator saturation
D.To store oil for the compressor crankcase
Explanation: The condenser desuperheats, condenses, and usually slightly subcools high-pressure refrigerant by rejecting heat to outdoor air or water. C-21D may replace condenser fans, motors, and coils on an existing unit, but not a complete remote condenser assembly.
7What does the compressor do to refrigerant vapor on an existing C-21D system?
A.It lowers pressure so liquid can boil in the condenser
B.It raises pressure and temperature so the condenser can reject heat
C.It meters liquid into the evaporator at constant superheat
D.It separates oil from liquid refrigerant in the liquid line
Explanation: The compressor takes low-pressure suction vapor and discharges it at a pressure high enough that outdoor air or water can condense it. Replacement of a failed compressor is expressly allowed C-21D work, provided the replacement matches the existing system design.
8What is superheat on an operating evaporator?
A.Saturated condensing temperature minus liquid-line temperature
B.Measured suction-line temperature minus saturated evaporating temperature at the suction pressure
C.Outdoor dry-bulb minus condensing temperature
D.Indoor wet-bulb minus evaporator saturation temperature
Explanation: Superheat is how many degrees the suction vapor is above saturation at the measured suction pressure. It confirms liquid has finished boiling before the compressor. Convert suction pressure to saturation temperature on the refrigerant P/T chart, then subtract that from the actual suction-line temperature.
9What is liquid-line subcooling?
A.Suction-line temperature minus saturated suction temperature
B.Discharge-line temperature minus outdoor dry-bulb
C.Evaporator leaving-air temperature minus entering-air temperature
D.Saturated condensing temperature minus actual liquid-line temperature
Explanation: Subcooling is how many degrees the liquid has been cooled below saturation at the liquid-line (or head) pressure. It confirms a solid liquid column at the metering device. Convert high-side pressure to saturated condensing temperature, then subtract the measured liquid-line temperature.
10What is the primary purpose of a liquid-line filter-drier on an existing refrigeration unit?
A.To store extra liquid refrigerant for high-load periods
B.To remove moisture, acid, and particulate from circulating refrigerant
C.To raise suction pressure during a hot pull-down
D.To replace the need for a vacuum after a repair
Explanation: A filter-drier’s desiccant and screen trap water, acid, and debris that would freeze at the metering device or damage the compressor. After any C-21D repair that opens the circuit, replace the drier and evacuate before recharge. A drier is not a receiver and does not skip evacuation.

About the NV C-21D Refrigeration and AC Maintenance Exam

The Nevada C-21D Refrigeration and Air Conditioning Maintenance Contractor Examination is the official Nevada State Contractors Board trade examination administered by PSI Services LLC. The official exam has 60 scored questions. Passing is 70% (42 of 60 points) in 2 hours. The examination is open book. Uniform Mechanical Code, 2018 (allowed in center). PSI lists USD 95 for one examination portion and USD 140 if taken with CMS; otherwise USD 95 per trade exam (Candidate Information Bulletin 270, updated 3/25/2026). NSCB requires a separate CMS examination for most new applicants, plus a USD 300 application fee and a USD 600 biennial license fee. This English-language MCQ bank is a study aid, not an official PSI form. It does not replace required trade experience, board approval, fingerprints, bonding, or the official examination.

Assessment

Open Book computer-based multiple-choice. Uniform Mechanical Code, 2018 (allowed in center)

Time Limit

2 hours

Passing Score

70% (42 of 60 points)

Exam Fee

USD 95 (PSI Services LLC (for the Nevada State Contractors Board))

NV C-21D Refrigeration and AC Maintenance Exam Content Outline

33%

Systems/Components

Systems/Components (20 items)

33%

Metering Devices/Troubleshooting

Metering Devices/Troubleshooting (20 items)

17%

Controls and Wiring

Controls and Wiring (10 items)

5%

Chilled Water

Chilled Water (3 items)

5%

Refrigerants

Refrigerants (3 items)

2%

Walk-in Refrigerators

Walk-in Refrigerators (1 items)

5%

Safety

Safety (3 items)

How to Pass the NV C-21D Refrigeration and AC Maintenance Exam

What You Need to Know

  • Passing score: 70% (42 of 60 points)
  • Assessment: Open Book computer-based multiple-choice. Uniform Mechanical Code, 2018 (allowed in center)
  • Time limit: 2 hours
  • Exam fee: USD 95

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

NV C-21D Refrigeration and AC Maintenance Study Tips from Top Performers

1Distribute study time to the official bulletin 270 content outline (updated 3/25/2026)
2Use only the PSI-listed references; temporary tabs such as Post-it notes are prohibited
3Confirm NSCB experience documentation before scheduling with PSI
4This bank is an English-language MCQ study aid, not an official PSI form

Frequently Asked Questions

How many questions are on the Nevada C-21D Refrigeration and Air Conditioning Maintenance Contractor Examination?

The official PSI examination has 60 scored questions. Passing is 70% (42 of 60 points) within 2 hours (Candidate Information Bulletin 270, updated 3/25/2026).

How much does the NV C-21D exam cost?

PSI lists USD 95 for one examination portion. Two portions cost USD 140 only if the second portion is CMS. NSCB charges a separate USD 300 application fee and USD 600 biennial license fee.

Is the NV C-21D exam open book?

Yes. PSI lists this examination as open book. Uniform Mechanical Code, 2018 (allowed in center)

Do I still need the CMS examination?

CMS is the required Nevada business-and-law examination. Most new applicants must pass CMS and a trade examination for the requested classification. In most cases you will not retake an exam if you have actively served as a qualified employee in the same classification within the last four years.