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100+ Free NV C-1A Boilers Practice Questions

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2026 Statistics

Key Facts: NV C-1A Boilers Exam

50 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-1A Boilers Contractor Examination is the official NSCB/PSI open book exam: 50 questions, 70% (35 of 50 points), 2 hours, USD 95 (bulletin 270, updated 3/25/2026). Official delivery: English.

Sample NV C-1A Boilers Practice Questions

Try these sample questions to test your NV C-1A Boilers exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the primary purpose of a safety or pressure-relief valve on a boiler?
A.Maintain a constant circulating-loop temperature during light load.
B.Automatically add makeup water when the system cools.
C.Indicate water level in the gauge glass during firing.
D.Prevent pressure from exceeding the boiler maximum allowable working pressure.
Explanation: A safety or pressure-relief valve is the last mechanical protection against overpressure. It must open at or below the boiler MAWP and relieve enough steam or water to keep the vessel from exceeding its rated pressure. UMC 2018 Chapter 10 treats this device as required boiler protection, not as a temperature or makeup control.
2Which installation practice is prohibited on a boiler safety or relief valve?
A.A full-size discharge pipe of the same diameter as the valve outlet.
B.A rigid discharge pipe approved for the system temperature.
C.A shutoff valve between the boiler tapping and the relief valve, or on the discharge pipe.
D.Support of the discharge pipe so it does not stress the valve body.
Explanation: UMC 2018 Section 1005.0 requires safety or relief valve discharge piping with no valves, obstructions, or means of isolation. A valve on either side of the relief connection can keep the valve from protecting the boiler. Discharge must remain at least the outlet size and must be supported so weight is not hung on the valve.
3A suspected natural-gas leak at a boiler gas train should be located with which method?
A.An open flame passed along fittings until the leak lights.
B.A listed combustible-gas detector or a noncorrosive leak-detection solution (soap test).
C.Oxygen introduced into the piping to raise the test pressure quickly.
D.A match at the relief-valve discharge to confirm draft.
Explanation: NFPA 54 (2012) requires leak checks with a listed detector or a leak-detection fluid. An open flame is an ignition source on a fuel leak. Oxygen is never used as a test medium. Finding a leak is a safety task, not a draft check at the relief valve.
4Per UMC 2018 Section 1005.0, how must a boiler safety or relief valve discharge be piped?
A.Reduced one pipe size, valved, and tied into the building sanitary stack.
B.Through a water-seal trap so steam cannot enter the room.
C.Into the expansion tank so discharged water is saved.
D.Full size, with no valves or obstructions, to a safe point such as within 18 inches of the floor or an open receptacle.
Explanation: UMC 2018 1005.0 requires unobstructed, full-size relief discharge piping. The Uniform Mechanical Code family pipes that discharge to within 18 inches of the floor or to an open receptacle so scalding water or steam is directed down and remains visible. A trap, a size reduction, a valve, or a connection into the expansion tank would keep the valve from relieving or hide a discharge.
5Using the indoor standard method, what minimum room volume is required for combustion air for a 120,000 Btu/h gas boiler?
A.1,200 cubic feet
B.2,400 cubic feet
C.6,000 cubic feet
D.12,000 cubic feet
Explanation: UMC 2018 701.4 and NFPA 54 (2012) 9.3.2.1 both use 50 cubic feet of indoor volume per 1,000 Btu/h of appliance input. 120,000 / 1,000 × 50 = 6,000 cubic feet. Direct-vent (sealed-combustion) appliances are omitted from that sum. If the actual room is smaller, outdoor openings under 701.6 / 9.3.3 are required.
6What does a low-water fuel cutoff do on an automatically fired steam or hot-water boiler?
A.It raises firing rate when the water line is low so remaining water boils faster.
B.It automatically stops the burner when the water level falls below the lowest safe level.
C.It opens the safety valve whenever the gauge glass is empty.
D.It equalizes pressure between the supply and return headers.
Explanation: UMC 2018 Chapter 10 requires automatically fired boilers to be protected by a low-water fuel cutoff (or a flow switch on some hot-water boilers). The device interrupts fuel so the heat-transfer surfaces are not fired dry. It does not speed the fire, operate the safety valve, or balance hydronic headers.
7Incomplete combustion at a gas- or oil-fired boiler is most dangerous because it can produce which product?
A.Pure nitrogen with no heating value.
B.Distilled water that floods the condensate trap.
C.Inert argon that dilutes the flame to yellow.
D.Carbon monoxide, a toxic, odorless gas.
Explanation: Starved or poorly mixed combustion converts carbon to carbon monoxide instead of carbon dioxide. CO is toxic and has no useful odor. Combustion-air shortages, blocked vents, and misadjusted burners are the usual causes. Complete combustion yields mainly CO2 and H2O plus excess air.
8Before a light-off attempt on an NFPA 85 single-burner boiler, the furnace must be purged with about how many air changes?
A.One air change at any damper position.
B.Eight air changes of the furnace and gas-pass volume.
C.Twenty-four air changes with the fuel valves open.
D.No purge is required if the last shutdown was less than one hour ago.
Explanation: NFPA 85 requires a proven prepurge that sweeps unburned fuel out of the furnace before an igniter is energized. For single-burner boilers the classic requirement is eight air changes of the furnace, setting, and gas passes. Fuel valves stay closed during purge. A recent shutdown does not waive the purge interlock.
9A hot-water heating boiler has a maximum output of 250,000 Btu/h. What is the minimum relieving capacity of its ASME pressure-relief valve?
A.250,000 Btu/h, at least equal to the boiler maximum output.
B.150,000 Btu/h, because 60 percent of output is enough.
C.30 psi, which automatically equals 30,000 Btu/h.
D.The same gpm as the circulator nameplate.
Explanation: The relief valve must be able to discharge heat as fast as the boiler can produce it, so its certified Btu/h capacity is at least the boiler maximum output (250,000 Btu/h here). Set pressure is a different rating — typically at or below MAWP, often 30 psi on residential cast-iron heating boilers — and is not converted into Btu/h by reading the psi number. Circulator flow is not a relief-capacity unit.
10A 180,000 Btu/h boiler takes all combustion air from outdoors through two vertical ducts. Metal louvers provide 75 percent free area. What minimum gross area is required for each opening?
A.18 square inches
B.45 square inches
C.60 square inches
D.180 square inches
Explanation: UMC 2018 701.6 and NFPA 54 (2012) 9.3.3 size each of two vertical outdoor openings at 1 square inch per 4,000 Btu/h: 180,000 / 4,000 = 45 in² net free area each. Metal louvers are taken as 75 percent free area (NFPA 54 9.3.4.1), so gross area = 45 / 0.75 = 60 in² each. Wood louvers would be 25 percent free area and would need a much larger grill.

About the NV C-1A Boilers Exam

The Nevada C-1A Boilers Contractor Examination is the official Nevada State Contractors Board trade or management examination administered by PSI Services LLC. The official exam has 50 scored questions. Passing is 70% (35 of 50 points) in 2 hours. The examination is open book. Approved center references include UMC 2018, NFPA 54 (2012), NFPA 31, NFPA 85 (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 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. UMC 2018, NFPA 54 (2012), NFPA 31, NFPA 85 (allowed in center)

Time Limit

2 hours

Passing Score

70% (35 of 50 points)

Exam Fee

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

NV C-1A Boilers Exam Content Outline

10%

Safety

Boiler safety (5 items)

16%

Fuel Oil

Fuel-oil systems (8 items)

16%

Gas

Gas-fired boilers (8 items)

30%

Hydronics

Hydronic systems (15 items)

4%

Valves and Controls

Valves and controls (2 items)

24%

Boilers

Boiler installation (12 items)

How to Pass the NV C-1A Boilers Exam

What You Need to Know

  • Passing score: 70% (35 of 50 points)
  • Assessment: Open Book computer-based multiple-choice. UMC 2018, NFPA 54 (2012), NFPA 31, NFPA 85 (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-1A Boilers 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-1A Boilers Contractor Examination?

The official PSI examination has 50 scored questions. Passing is 70% (35 of 50 points) within 2 hours (Candidate Information Bulletin 270, updated 3/25/2026).

How much does the NV C-1A Boilers 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-1A Boilers exam open book?

Yes. PSI lists this examination as open book. UMC 2018, NFPA 54 (2012), NFPA 31, NFPA 85 (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.