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Key Facts: NV C-21E Solar Air Conditioning Exam

45 Q

Official Exam Questions

PSI Nevada Contractor CIB updated 3/25/2026

32 of 45 points

Passing Score

PSI Nevada Contractor CIB updated 3/25/2026

1.5 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-21E Solar Air Conditioning Contractor Examination is the official NSCB/PSI open book exam: 45 questions, 32 of 45 points, 1.5 hours, USD 95 (bulletin 270, updated 3/25/2026). Official delivery: English.

Sample NV C-21E Solar Air Conditioning Practice Questions

Try these sample questions to review concepts for the NV C-21E Solar Air Conditioning exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under NAC 624.380, what work does a Nevada C-21E Solar Air-Conditioning license authorize?
A.Installation of collectors, piping, storage, and other equipment that convert solar energy into energy used to control air temperatures
B.Installation of photovoltaic modules and inverters that power conventional vapor-compression air conditioners
C.Installation of unglazed collectors used only to heat swimming pools
D.Service of any refrigeration compressor regardless of whether solar collectors are present
Explanation: NAC 624.380(3)(e) defines C-21e as installation of the collectors, piping, storage, and other equipment used to convert solar energy to energy used for the control of air temperatures. That is a solar-thermal hydronic and absorption-cooling scope inside the C-21 refrigeration and air-conditioning family. Photovoltaic generation is C-2G, and pool heating is outside this classification.
2Which tubing is the usual choice for a pressurized solar collector loop that can stagnate well above 250°F on a Nevada roof?
A.PEX-A rated 180°F at 100 psi
B.Type L copper tube
C.Schedule 40 PVC
D.Flexible elastomeric hose listed only to 140°F
Explanation: A glazed collector can stagnate at 300°F to 400°F. Type L copper is the common hydronic material for those temperatures and is listed in UPC Chapter 6 for water distribution. PEX, PVC, and low-temperature hose exceed their ratings in a stagnating collector loop and are not acceptable on that circuit.
3Per UPC 2018 Table 313.3, what is the maximum horizontal hanger spacing for 1-inch soldered copper tube on a solar hydronic run?
A.4 feet
B.6 feet
C.10 feet
D.12 feet
Explanation: UPC 2018 Table 313.3 lists copper and copper-alloy tube with soldered, brazed, threaded, or mechanical joints at 6 feet horizontally for 1-1/2 inches and smaller, and 10 feet for 2 inches and larger. One-inch tube is in the 6-foot column. Vertical copper is supported at each floor, not to exceed 10 feet.
4Why is PEX generally prohibited on the collector side of a closed-loop solar air-conditioning system even though it is listed for some hydronic heating?
A.PEX cannot be insulated
B.Collector stagnation and generator-loop temperatures routinely exceed PEX pressure-temperature ratings
C.PEX is not allowed anywhere under the UPC
D.PEX cannot be joined with mechanical fittings
Explanation: Typical PEX listings are on the order of 180°F at 100 psi. A glazed or evacuated-tube array serving an absorption generator can run 160°F to 210°F in service and far hotter in stagnation. FSEC solar-thermal practice keeps plastics off that circuit and uses copper or steel. PEX may still appear on a lower-temperature chilled-water or radiant-panel circuit downstream of a heat exchanger.
5A copper solar collector supply is connected to a steel storage-tank fitting. What UPC joint practice prevents galvanic corrosion at that connection?
A.A dielectric union or other approved dielectric fitting
B.A PVC coupling
C.Soft solder only, with no dielectric
D.Leaving a 1-inch air gap in the pipe
Explanation: UPC joining rules require an approved dielectric union or equivalent when copper is joined to ferrous pipe or tanks in water systems. The insulator breaks the galvanic cell that would otherwise pit the steel. The fitting must remain accessible. Dissimilar-metal contact is a common leak point on solar storage tanks.
6On the chilled-water piping that leaves a solar-driven absorption chiller, where must the vapor retarder be placed?
A.Against the pipe wall, under the insulation
B.On the outside of the insulation, sealed at every joint and penetration
C.Only on the chiller evaporator barrel
D.Vapor retarders are not used on chilled-water pipe
Explanation: Chilled-water pipe runs below ambient dew point, so moisture drives inward. The vapor retarder belongs on the warm (outer) face and must be continuous. A break at a hanger or valve becomes a condensation and mold site. Hot generator-loop insulation does not need that same exterior retarder, but the chilled side of a solar air-conditioning plant does.
7How must collector-loop piping be pitched on a drainback solar air-conditioning system?
A.Level, so the pump does not have to work against gravity
B.Continuously back to the drainback reservoir so the collectors and roof piping empty when the pump stops
C.Up toward the collectors so air is trapped at the array
D.Only the return pipe is pitched; the supply may hog
Explanation: Drainback freeze and overheat protection works only if every collector riser and roof header drains to the indoor reservoir when the pump shuts off. FSEC solar-thermal practice requires a continuous pitch with no belly that holds water. Trapped water in a Nevada high-desert night or a Reno freeze will split the absorber.
8Per UPC 2018 Table 313.3, what is the maximum horizontal hanger spacing for 3/4-inch solvent-cemented CPVC used on a lower-temperature hydronic run?
A.32 inches
B.3 feet
C.6 feet
D.10 feet
Explanation: Table 313.3 lists solvent-cemented CPVC at 3 feet horizontally for 1 inch and smaller, and 4 feet for 1-1/4 inches and larger. Three-quarter-inch CPVC is in the 3-foot column. Vertical CPVC is supported at the base and each floor with mid-story guides. Do not apply the copper 6-foot spacing to CPVC.
9Per UPC 2018 Table 313.3, what is the maximum horizontal hanger spacing for 3/4-inch PEX?
A.32 inches
B.3 feet
C.4 feet
D.6 feet
Explanation: Table 313.3 lists PEX with cold-expansion, insert, or compression joints at 32 inches horizontally for 1 inch and smaller, and 4 feet for 1-1/4 inches and larger. Three-quarter-inch PEX takes 32-inch spacing. Vertical PEX is supported at the base and each floor with mid-story guides.
10Per UPC 2018 Table 313.3, what is the maximum horizontal hanger spacing for 1-inch threaded steel pipe carrying water?
A.6 feet
B.8 feet
C.10 feet
D.12 feet
Explanation: Table 313.3 lists steel pipe for water or DWV at 10 feet horizontally for 3/4 inch and smaller, and 12 feet for 1 inch and larger. One-inch water steel is therefore 12 feet. Do not use the steel-for-gas row, which is tighter (8 feet at 3/4 and 1 inch).

About the NV C-21E Solar Air Conditioning Exam

The Nevada C-21E Solar Air Conditioning Contractor Examination is the official Nevada State Contractors Board trade examination administered by PSI Services LLC. The official exam has 45 scored questions. Passing is 32 of 45 points in 1.5 hours. The examination is open book. Uniform Plumbing 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.

Exam sponsor: PSI Services LLC (for the Nevada State Contractors Board). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

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

Time Limit

1.5 hours

Passing Score

32 of 45 points

Exam / Certification Fees

USD 95

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

22%

Piping

Piping (10 items)

33%

System Design

System Design (15 items)

11%

Pumps and Storage Systems

Pumps and Storage Systems (5 items)

16%

Collectors

Collectors (7 items)

7%

System Valves and Controls

System Valves and Controls (3 items)

11%

Safety

Safety (5 items)

Preparing for the NV C-21E Solar Air Conditioning Exam

What You Need to Know

  • Passing score: 32 of 45 points
  • Assessment: Open Book computer-based multiple-choice. Uniform Plumbing Code, 2018 (allowed in center)
  • Time limit: 1.5 hours
  • Exam / certification fees: USD 95 Official sources

Using Our Practice Resources

  • 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-21E Solar Air Conditioning: Suggested Study Strategy

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-21E Solar Air Conditioning Contractor Examination?

The official PSI examination has 45 scored questions. Passing is 32 of 45 points within 1.5 hours (Candidate Information Bulletin 270, updated 3/25/2026).

How much does the NV C-21E 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-21E exam open book?

Yes. PSI lists this examination as open book. Uniform Plumbing 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.