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The NV-C1 exam has 120 questions and runs 5 hours.
These 10 free NV-C1 questions are organized by exam domain, so you can see how each part of the Nevada Plumbing and Heating Contractor (C-1) Trade Exam blueprint is tested. Reveal the answer and explanation under each question.
A cast-iron heating boiler has continued firing after a confirmed loss of water and shows signs of severe overheating. Its fuel supply has now been shut off from a safe location. The proposed recovery plans differ mainly in how they restore water. Which plan should the contractor follow?
Correct answer: D - Keep the boiler isolated; let it cool naturally before inspection and any refilling.
Size a natural-gas branch serving a boiler rated 130,000 Btu/h input and a water heater rated 50,000 Btu/h input. A separate 200,000-Btu/h appliance connects upstream of this branch. Gas heating value is 1,000 Btu/ft³. The longest-length method requires the 60-ft row. The applicable table, for 0.60-specific-gravity gas and a 0.5-in. water-column pressure drop, lists 65, 138, 259, and 532 ft³/h for 1/2-in., 3/4-in., 1-in., and 1-1/4-in. pipe, respectively. Select the smallest adequate branch size.
Correct answer: C - 1-in. pipe
At an adult accessible lavatory, a listed temperature-limiting valve delivers water at the specified 115 °F. The water-supply and drain pipes beneath the bowl are exposed where a user's legs can contact them; they have neither insulation nor a protective enclosure. The required knee and toe clearances are otherwise satisfied. What remains necessary under Section 606.5 of the 2010 ADA Standards?
Correct answer: D - Protect the exposed supply and drain piping against contact without reducing required clearances.
A fully filled, closed-loop hydronic system needs 20 gpm. At that flow, the complete circuit loses 18 ft of head through its piping, boiler, fittings, and control valves. The highest emitter is 60 ft above the circulator. Cold fill pressure, high-point pressure, and pump suction conditions have already been verified as adequate. Which operating duty belongs on the circulator schedule?
Correct answer: A - 20 gpm at 18 ft of differential head
After a water meter is replaced, a home's pressure is 56 psig with the water heater cold. With all outlets closed, pressure climbs to 106 psig during a normal heating cycle, then falls promptly when a faucet opens. Pressure upstream of the meter remains steady. The replacement meter contains a check valve, and no expansion-control device is installed. What best addresses this pressure pattern?
Correct answer: B - Install a properly sized potable-water expansion tank downstream of the check valve.
An office conversion has plumbing fixtures on a lower floor at elevation 96 ft and an upper floor at elevation 108 ft. The next upstream public-sewer manhole cover is at elevation 101 ft. Both floors can drain to the sewer by gravity. Under the 2018 Uniform Plumbing Code, how should backwater protection be arranged?
Correct answer: A - Protect the lower-floor branch; connect the upper-floor drain downstream of that valve.
A potable-water connection supplies a chemical-injection irrigation system. The chemicals constitute a health hazard, and a downstream booster can raise pressure above the potable supply pressure. The connection remains pressurized between irrigation cycles. The authority having jurisdiction permits an approved mechanical backflow assembly for this application. Which assembly provides the required protection?
Correct answer: B - Reduced-pressure principle assembly
A relocated laundry standpipe has a 2-in. P-trap and a 2-in. horizontal trap arm sloped at 1/4 in. per ft. The developed distance from the trap weir to the inner edge of the vent connection is 6 ft 8 in. All other fixture and vent details comply with the 2018 Uniform Plumbing Code. Which revision corrects the trap-arm violation?
Correct answer: C - Relocate the vent connection to produce a 4-ft trap arm at the existing slope.
Two parallel pipe runs require a rolling offset with a 12-in. horizontal roll and a 16-in. vertical rise, using two 45-degree elbows. The net fitting takeout is 1.25 in. at each end of the connecting straight pipe, already accounting for joint engagement. What straight-pipe cut length is required, to the nearest tenth of an inch?
Correct answer: B - 25.8 in.
The sprinkler sequence specified for an archive admits water into normally dry piping when the detection system operates. Intact sprinklers do not discharge at that stage. Conversely, opening a sprinkler without a detection signal does not admit the main water supply. Identify the system that matches both requirements.
Correct answer: B - Single-interlock preaction system
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