Nevada C-37 Solar Contractor Examination

For a glazed flat-plate collector loop serving potable or glycol solar water heating under C-37 practice, which piping material is the usual choice because it can survive collector stagnation temperatures of 300°F and higher?

• ASchedule 40 PVC
• BPEX-A rated only to 180°F
• CABS DWV
• DType L copper tube

Which piping material is accepted on an unglazed C-37D-type solar pool array where water temperatures stay near pool temperature?

• ASchedule 40 PVC sized for the array flow
• BThin-wall DWV PVC used as a pressure line
• CUnlisted garden hose
• DType M copper with 50/50 solder and no insulation

Per 2018 UPC Table 313.3, horizontal copper or copper-alloy tubing 1-1/2 inches and smaller on a solar collector loop shall be supported at intervals not exceeding which spacing?

• A4 feet
• B12 feet
• C10 feet
• D6 feet

A drainback C-37 water- or space-heating array must empty by gravity when the pump stops. What continuous slope does FSEC practice require on collectors and outdoor piping?

• ALevel piping is acceptable if the pump is oversized
• BA high point in the middle of the array so water splits both ways
• C2 inches per foot toward the street
• D1/4 inch per foot back to the indoor drainback reservoir

Outdoor solar supply and return piping on a C-37 glazed system shall be insulated and then protected how?

• ALeft bare so the sun can add extra heat
• BBuried without insulation if the trench is 6 inches deep
• CWrapped only with duct tape at the hangers
• DCovered with a UV-resistant jacket or coating so the insulation does not degrade

Per 2018 UPC Sections 605.15 and 605.16, copper solar tubing joined to galvanized steel tank fittings shall include which fitting?

• AA dielectric union or other listed dielectric fitting
• BA no-hub soil coupling
• CA sanitary tee laid on its back
• DA PVC female adapter solvent-welded to the copper

Why is CPVC generally rejected for the outdoor run of a glazed C-37 collector loop even though it is a hot-water plumbing plastic?

• ACPVC cannot be solvent-welded
• BThe UPC bans all plastic on any solar job including unglazed pools
• CCPVC is only listed for underground gas
• DCollector stagnation temperatures exceed the CPVC pressure-temperature rating

A C-37 glazed array of four collectors is piped reverse-return (Tichelmann). What is the purpose of that layout?

• ATo make the first collector receive all the flow
• BTo convert the system from thermal to photovoltaic
• CTo drain only the last collector in a freeze
• DTo give each collector nearly the same total supply-plus-return path length so flow balan…

Compared with piping glazed collectors in parallel, piping two collectors in series is chosen when the designer wants which result?

• AA larger flow and a smaller temperature rise through the pair
• BA legal substitute for a T&P valve
• CAutomatic freeze protection without slope or glycol
• DA smaller flow through each absorber and a larger temperature rise, useful on a solar-AC…

Long copper collector headers on a hot Nevada roof need expansion accommodation because copper grows about 1.1 inches per 100 feet per 100°F. Which installation detail is correct?

• AAnchor the pipe rigidly at every rafter with no slack
• BSwitch the entire glazed loop to Schedule 40 PVC so it will not expand
• CFill the pipe with sand so it cannot move
• DProvide expansion loops, offsets, or swing joints and do not lock the pipe at both ends

A C-37 installer joins Type L copper to a steel storage-tank tapping without a dielectric and without a bronze dielectric nipple. What is the expected failure?

• AThe copper tube work-hardens and splits from vibration only
• BThe UPC requires no protection because both metals carry water
• CThe joint becomes a listed double-wall heat exchanger
• DGalvanic corrosion attacks the steel fitting and leaks at the joint

FSEC and copper-tube practice keep glazed collector-loop velocity in about which range to limit erosion, noise, and pressure drop?

• A0.2 to 0.4 feet per second
• BVelocity is not limited if the pump is a wet-rotor circulator
• C15 to 20 feet per second
• D2 to 5 feet per second

A glazed DHW array is designed for 1.2 gpm. Which Type L copper size is the usual FSEC choice for that collector-loop flow while staying near 4 fps?

• A3/8 inch Type L (about 0.9 gpm at 4 fps) as the only run
• B4 inch Schedule 40 PVC
• C2 inch Type L so velocity stays under 0.5 fps
• D1/2 inch Type L (about 2.9 gpm at 4 fps) or 3/4 inch if the run is long

A C-37D-scope pool array is designed for 36 gpm. Using FSEC header practice (about 1-1/2 inch to 30 gpm and 2 inch to 50 gpm), which PVC header is correct?

• A3/4 inch Schedule 40 PVC
• B1 inch Schedule 40 PVC
• C2 inch Schedule 40 PVC
• D4 inch DWV used as a pressure header

A drainback C-37B space-heating array has a 20-foot outdoor return with a 2-inch sag at mid-span. What is the field correction?

• ALeave the sag; the pump will blow the pocket clear every morning
• BCap the return and operate as a thermosiphon
• CAdd ethylene glycol and ignore the sag
• DRepitch the return at 1/4 inch per foot with no low pockets so the line empties to the in…

Near a glazed collector outlet that can stagnate above 300°F, which copper joint method is the FSEC-preferred choice?

• A50/50 tin-lead solder
• BDuct-tape wrap over a slipped coupling
• CSolvent-welded CPVC transition
• DBrazing or a high-temperature solder/press system listed for solar stagnation temperatures

Where a C-37 copper collector loop penetrates a composition roof, the 2018 UPC protection-of-piping rules plus FSEC weatherproofing require which detail?

• AAn unflashed hole caulked with roofing tar only
• BNo flashing if the hole is on the north slope
• CA PVC boot solvent-welded to the copper
• DA listed roof flashing or pitch pan, pipe insulation stopped short of the flashing so the…

On a closed-loop glycol C-37 system that does not drain back, where are automatic or manual air vents placed?

• AOnly on the cold-water meter
• BAir vents are prohibited on all solar systems
• COn the T&P discharge pipe
• DAt the high points of the collector array and piping so trapped air can be released

A 3/4 inch Type L collector loop has 80 feet of pipe, eight 90-degree elbows (2 feet equivalent each), and four tees through the branch (4 feet equivalent each). What is the total equivalent length used for pump-head calculations?

• A80 feet
• B96 feet
• C112 feet
• D160 feet

Using 2.45 × ID² × velocity (gpm), a 3/4 inch Type L tube (ID 0.785 in.) at 4 fps carries about 6.0 gpm. A glazed array needs 2.4 gpm. What is the approximate velocity in that 3/4 inch tube?

• A0.4 fps
• B10 fps
• C4.0 fps
• D1.6 fps

A 80-foot copper collector header is installed at 40°F and later stagnates at 220°F (180°F rise). Using 9.4 × 10⁻⁶ in/in-°F, how much will that header grow?

• A0.16 inch
• B0.80 inch
• C1.6 inches
• D8.0 inches

Four glazed collectors, each 4 ft by 8 ft, are piped in parallel at the FSEC high-flow rate of 0.015 gpm per square foot. What total collector-loop flow should the installer set?

• A0.48 gpm
• B15.0 gpm
• C4.80 gpm
• D1.92 gpm

Under NAC 624.540, what may a person who holds the parent classification C-37 license design, fabricate, and install?

• AOnly photovoltaic modules and inverters
• BOnly interior potable fixture rough-in with no collectors
• COnly swimming-pool pumps and filters with no collectors
• DSystems for the collection of solar energy to heat and cool water, air, and chemicals

A customer wants rooftop photovoltaic modules, an inverter, and a grid interconnection. Why is that work outside the C-37 examination scope?

• AC-37 covers photovoltaic modules as long as they also heat water
• BC-37 automatically includes every electrical trade
• CNevada does not license any solar work
• DPhotovoltaic electric generation is classification C-2G; C-37 is solar thermal

How does parent C-37 differ from subclassification C-37A (solar water heating) in NAC 624.540?

• AThere is no difference; the two licenses have identical scope
• BC-37A is limited to swimming-pool collectors
• CC-37A is the only classification that may install photovoltaic arrays
• DC-37A is limited to potable-water heating and may not install pipes or fixtures other tha…

NAC 624.540(2)(b) authorizes C-37B space-heating work including storage, piping, and heat exchangers, but it expressly excludes which equipment?

• AHeat exchangers of every kind
• BAny piping inside a building
• CAir-handling solar collectors
• DEquipment for pools

What does NAC 624.540(2)(c) authorize under C-37C solar air-conditioning — and what does it not authorize?

• AInstallation of collectors, piping, storage, and other equipment that convert solar energ…
• BInstallation of vapor-compression air conditioners powered only by utility electricity
• CInstallation of photovoltaic modules and inverters only
• DInstallation of swimming-pool filters only

NAC 624.540(2)(d) lets a C-37D contractor install collectors, piping, and heat exchangers that heat swimming pools and spas with solar energy, but it does not include which work?

• AThe solar collectors themselves
• BPiping that carries pool water to the solar array
• CHeat exchangers used to heat the pool
• DThe plumbing of swimming pools or the installation of their equipment

In the Northern Hemisphere, toward which true direction should fixed C-37 collectors face for maximum daily solar radiation?

• ATrue east
• BTrue west
• CTrue south
• DMagnetic north

For year-round domestic water heating in Nevada, FSEC's fixed-tilt rule of thumb sets collector tilt equal to which value?

• AZero degrees (flat)
• BNinety degrees (vertical wall)
• CLatitude plus 45 degrees
• DThe site latitude

FSEC estimates residential hot-water use at about which daily volume per person when sizing a C-37 potable solar water heater?

• A2 gallons per person per day
• B200 gallons per person per day
• C80 gallons per person per day
• D20 gallons per person per day

A C-37B winter space-heating array in Reno (latitude about 39.5°N) should be tilted by which FSEC rule?

• ALatitude minus 15 degrees (about 24°)
• BThe same flat mount used for a summer pool array
• CZero degrees so snow slides off
• DLatitude plus 10 to 15 degrees (about 50–55°)

A C-37D unglazed pool array in Las Vegas (latitude about 36°N) is optimized for the summer swim season. Which tilt matches FSEC practice?

• ALatitude minus 10 to 15 degrees, or the existing low roof pitch
• BLatitude plus 15 degrees (about 51°)
• C90 degrees (vertical)
• DFacing true north at latitude tilt

Using the FSEC/DOE Sun Belt rule of 20 ft² of glazed collector for each of the first two occupants and 8 ft² for each additional occupant, what collector area is indicated for a family of four in Las Vegas?

• A20 ft²
• B36 ft²
• C56 ft²
• D160 ft²

FSEC storage practice uses 1.5 to 2.0 gallons of solar storage per square foot of glazed collector. At 1.5 gal/ft², what storage volume matches a 56 ft² DHW array?

• A28 gallons
• B56 gallons
• C84 gallons
• D280 gallons

A 64 ft² glazed DHW array is commissioned at the FSEC high-flow rate of 0.020 gpm per square foot. What flow should the setter read?

• A0.20 gpm
• B0.64 gpm
• C1.28 gpm
• D12.8 gpm

A glazed C-37 DHW loop circulates 1.20 gpm of water with an 18°F temperature rise. Using Q = 500 × gpm × ΔT, what heat is being delivered?

• A1,080 Btu/h
• B9,000 Btu/h
• C10,800 Btu/h
• D108,000 Btu/h

In an FSEC two-tank potable solar water heater, how are the tanks arranged?

• AThe solar tank preheats water that then feeds the backup water heater
• BThe backup heater feeds cold water into the collectors
• CThe two tanks sit in parallel on the cold inlet with no series connection
• DThe solar tank is used only as an expansion tank

Northern Nevada winter nights routinely drop below freezing and southern valleys still see freeze events. Which C-37 DHW designs are the FSEC-accepted freeze methods?

• ADrainback (collectors empty by gravity) or a closed glycol loop with the correct heat exc…
• BOpen-loop potable water left in the collectors all winter under city pressure
• CAn ICS batch collector with no freeze valve on a Reno roof
• DRecirculating 40°F city water through uninsulated 3/8 inch tubing with no control

Compared with a closed glycol C-37 loop, a drainback system’s distinctive design requirement is which of the following?

• AA high-head pump, a reservoir below the array, and continuous pitch so the collectors emp…
• BA double-wall heat exchanger for food-grade propylene glycol
• CAn unglazed pool collector as the only absorber
• DNo pump of any kind

Why is an integral-collector-storage (ICS / batch) water heater a poor C-37 choice for a Reno residence?

• AThe large volume of water stored in the roof-mounted absorber is difficult to protect fro…
• BICS collectors cannot face south
• CICS systems are photovoltaic and belong to C-2G
• DThe UPC bans all solar storage

A passive thermosiphon C-37 water heater circulates without a pump. Where must the storage tank sit relative to the collectors?

• AAbove the collectors so heated water rises into the tank and cooler water falls back
• BBelow the collectors so the pump can lift the water
• COn a north wall with no elevation difference
• DInside the collector box

A four-person DHW load is 80 gallons heated 70°F (80 × 8.33 × 70 = 46,648 Btu/day). A 56 ft² array delivers 1,200 Btu/ft²-day at 50 percent system efficiency. What is the daily solar fraction?

• AAbout 18 percent
• BAbout 36 percent
• CAbout 72 percent
• DAbout 144 percent

A 2,000 ft² Reno house is to get a C-37B combi system. The designer uses 1 ft² of glazed collector per 10 ft² of floor for a meaningful winter solar fraction. What collector area does that rule give, and how should tilt be set?

• A20 ft² at latitude minus 15 degrees
• B80 ft² facing true north
• C200 ft² at latitude plus 10 to 15 degrees
• D2,000 ft² of unglazed pool collectors at 0 degrees

Why do C-37B hydronic space-heating designs prefer radiant floors or large coils over high-temperature fin-tube?

• ARadiant floors accept 90–120°F water, which glazed collectors can deliver efficiently
• BFin-tube is banned by NAC 624.540
• CRadiant floors require unglazed pool collectors
• DThe UPC requires every solar space-heat system to be steam

A C-37C single-effect lithium-bromide absorption chiller needs a generator temperature of about 180–210°F. Which collector type is the realistic C-37 choice?

• AEvacuated-tube or concentrating collectors piped for high-temperature delivery
• BUnglazed black plastic pool collectors
• CPhotovoltaic modules feeding the building panelboard
• DICS batch heaters at 100°F

A C-37C single-effect absorption chiller has a thermal COP of 0.70 and must deliver 3 tons (36,000 Btu/h) of cooling. About how much solar-heat input is required at that COP?

• A10,800 Btu/h
• B25,200 Btu/h
• C51,400 Btu/h
• D360,000 Btu/h