Nevada C-37A Solar Water Heating Contractor Examination

Under NAC 624.540, which piping may a C-37A solar water-heating contractor install?

• AThe water heater, storage tank, and piping that belong to the potable solar water-heating…
• BThe entire building potable-water distribution system to every fixture
• CSwimming-pool circulation piping and spa equipment
• DHydronic space-heating supply and return mains

Which copper tube type is the usual choice for a pressurized solar collector loop serving potable domestic hot water?

• AType DWV copper, because collector loops are not under pressure
• BType M only, because solar loops never exceed 100°F
• CType L copper tube, listed for hot-water service and the temperatures a glazed collector…
• DSoft Type K refrigeration coil without joints

What is the primary reason solar collector-loop and solar-tank piping is insulated?

• ATo raise the pipe's pressure rating
• BTo replace the need for a temperature-and-pressure relief valve
• CTo make Type M copper acceptable for buried service
• DTo cut heat loss so collected energy reaches the storage tank and stays there

When copper collector-loop tubing is joined to a steel tank fitting, what fitting is required to limit galvanic corrosion?

• AA dielectric union or other listed dielectric fitting
• BA PVC coupling
• CA rubber hose barb
• DNo special fitting; solder the copper directly to the steel

Outdoor solar collector piping insulation must be protected from ultraviolet light by which method?

• ALeaving the foam bare so it can dry after rain
• BPainting closed-cell foam with leftover latex wall paint only
• CA UV-resistant jacket, cladding, or insulation listed for outdoor exposure
• DWrapping the pipe in polyethylene vapor-barrier film only

In a drainback solar water-heating system, outdoor collector piping is pitched so that it will do which of the following when the pump stops?

• AHold a full water charge so the next start is instant
• BVent steam to the roof so the loop can boil dry
• CTrap a glycol slug at each collector header
• DDrain completely by gravity into the indoor drainback reservoir

Why is ordinary PEX generally not used for the roof collector loop of a glazed solar water heater?

• APEX cannot be used on any hot-water line in the 2018 UPC
• BPEX cannot be insulated
• CPEX is electrically conductive and will short the differential controller
• DCollector stagnation temperatures can exceed PEX temperature ratings

Per 2018 UPC Table 313.3, what is the maximum horizontal hanger spacing for 3/4-inch copper water tube?

• A32 inches
• B4 feet
• C6 feet
• D12 feet

Per 2018 UPC Section 609.4, a completed potable hot-and-cold water piping section shall be tested how?

• AWith 10 psi air for 5 minutes
• BA visual inspection only; pressure tests are not required on solar piping
• CWith 100 psi nitrogen for 1 hour on every material including plastic
• DWith potable water at not less than working pressure, or (except plastic) 50 psi air, hel…

Long copper collector-loop runs on a hot roof need expansion accommodation. Which detail is correct?

• AAnchor the tube rigidly at both ends so it cannot move
• BUse expansion loops, offsets, or flexible connectors so thermal growth does not break joi…
• CRely on solder joints to stretch with the tube
• DOmit hangers so the tube can slide freely on the roofing

Compared with Type L, Type M copper tube on a solar collector loop is a poor choice mainly because it has which characteristic?

• AA thinner wall that leaves less corrosion and mechanical allowance at collector temperatu…
• BA thicker wall that will not accept ordinary solder fittings
• CNo listing for any potable-water use
• DA plastic liner that melts at 120°F

Where solar collector piping passes through a roof, the penetration must be detailed to do which of the following?

• ALeave an unflashed oversize hole so the pipe can expand
• BRely on spray foam alone as the weather seal
• CUse listed flashing and a weathertight, UV-stable seal so rain cannot enter the building
• DSolder the copper tube directly to the asphalt shingles

Unions and isolation valves on a solar water-heating collector loop are installed so that which task can be done without draining the whole house?

• ARemoving the collectors, pump, or heat exchanger for service
• BBypassing the T&P valve during a pressure test
• CConnecting the collector loop to the swimming-pool filter
• DUsing the solar loop as a substitute building water service

A circulator that moves potable water in a direct (open-loop) solar DHW system should have which wet-end material?

• AStandard cast-iron boiler circulator
• BGalvanized irrigation pump
• CAluminum body with no listing
• DBronze, stainless-steel, or other listed potable-water circulator

A drainback collector array has a sag in the return line on the roof. What is the most likely winter failure?

• AThe pump will over-speed and cavitate in summer only
• BWater trapped in the sag can freeze, split the tube, and disable drainback protection
• CThe mixing valve will lose its ASSE 1017 listing
• DThe T&P valve will be required to discharge continuously

Sensor wiring that runs with solar piping should be installed so that it is protected how?

• ASpliced with wire nuts stuffed into the pipe insulation and left exposed on the roof
• BOmitted; the controller can estimate collector temperature from tank temperature alone
• CRun inside the potable copper water tube
• DRated for the temperature, protected from UV and abrasion, and kept dry at the sensor

Underground potable piping that connects a remote solar storage tank must comply with which 2018 UPC installation rule?

• AIt may be bare Type M copper laid in cinders with no wrap
• BIt must be orange non-potable reclaimed-water pipe
• CIt must be approved for underground use, protected from corrosion, and installed to the b…
• DIt is exempt from UPC because it is solar, not plumbing

On an indirect glycol solar DHW system, which piping contains the heat-transfer fluid rather than potable water?

• AThe cold-water inlet to the house only
• BThe closed collector loop between the collectors and the heat exchanger
• CThe tempered 120°F branch to the showers
• DThe T&P discharge pipe

A drainback reservoir must be sized to hold at least which volume?

• AThe volume of the backup gas water heater only
• BThe volume of the collectors plus the outdoor and attic piping that must drain, plus a re…
• COne gallon per occupant, regardless of collector area
• DThe entire 80-gallon potable storage tank

A 64-square-foot glazed collector array is piped for a typical high-flow collector loop at about 0.04 gallons per minute per square foot. What flow should the installer target?

• AAbout 0.4 gpm
• BAbout 16 gpm
• CAbout 2.6 gpm
• DAbout 64 gpm

An installer threads a copper male adapter directly into a galvanized steel tank tapping without a dielectric fitting. What is the expected result?

• AThe joint becomes a listed potable dielectric assembly
• BUPC 603.5.4 is satisfied because copper is nontoxic
• CThe copper becomes the anode and is protected indefinitely
• DGalvanic corrosion at the steel tapping, with leaks and rust in the potable water

An open-loop potable collector array in northern Nevada is piped with an uninsulated, unpitched 20-foot attic run and no automatic drain or recirculation freeze valve. What is the governing risk?

• AThe pipe will be too efficient and over-cool the tank every night
• BA hard freeze can split the potable collector piping and dump the tank into the attic
• CThe T&P valve will freeze first and protect the array
• DUPC 408.3 will automatically limit freeze damage to 120°F

What water use is inside the Nevada C-37A license scope?

• AHeating potable domestic water with solar collectors
• BHeating a swimming pool with unglazed collectors
• CHeating building air with a solar space-heating coil
• DInstalling a solar-assisted chilled-water air conditioner

In solar DHW design, what is an open-loop (direct) system?

• AA system that pumps potable water through the collectors and back to the storage tank
• BA system that uses only air as the heat-transfer fluid
• CA system that heats a swimming pool without a tank
• DA system that never needs a temperature-and-pressure relief valve

What is the defining feature of an indirect (closed-loop) solar water heater?

• AThe collectors have no absorber plate
• BThe storage tank is banned and water is heated only in the fixtures
• CThe system may legally omit backflow protection because the fluid is always potable
• DA separate heat-transfer fluid loop delivers heat through a heat exchanger to the potable…

In the northern hemisphere, potable solar collectors should face which direction for best year-round DHW performance?

• ATrue north
• BDue west only
• CTrue south
• DStraight up, regardless of latitude

For year-round domestic water heating, FSEC practice sets collector tilt at approximately which angle?

• AZero degrees (flat to the roof), always
• BThe site latitude
• CNinety degrees (vertical), always
• DThe roof pitch plus 45 degrees

The FSEC rule of thumb for glazed solar DHW collector area is which value?

• A2 square feet per person
• B10 square feet of collector per person
• C50 square feet per person
• D100 square feet per bedroom, regardless of occupancy

Using the FSEC storage rule of thumb, how much solar DHW storage should be provided per occupant?

• A5 gallons
• B200 gallons per person
• C80 gallons, regardless of occupancy
• D20 gallons

Why does a residential solar water heater still include a conventional backup water heater or backup element?

• AThe 2018 UPC bans solar heat from ever entering the potable tank
• BBackup heat is required only for swimming-pool systems
• CSolar input varies with weather and occupancy, so backup heat covers cloudy days and nigh…
• DThe backup heater replaces the T&P valve

In a typical two-tank potable solar DHW layout, the solar tank is piped to do which job?

• APreheat cold water before it enters the backup water heater
• BHeat only the swimming-pool return line
• CReplace the building cold-water service
• DDump collector fluid into the house fixtures when the pump is off

A homeowner asks a C-37A contractor to add unglazed collectors to heat the swimming pool with the same potable DHW array. What is the correct response?

• ATie the pool into the potable solar tank; C-37A covers all solar water
• BRefuse the pool tie-in as C-37A work; pool solar is a different classification and is not…
• CUse ethylene glycol in the potable tank so the pool and house can share fluid
• DOmit the mixing valve because pool water is cooler

Using the FSEC 10-square-foot and 20-gallon rules, what collector area and storage volume fit a four-person household?

• A10 square feet and 20 gallons
• B20 square feet and 40 gallons
• C40 square feet and 80 gallons
• D120 square feet and 20 gallons

DOE/Energy Savers Sun Belt collector sizing uses about 20 square feet for each of the first two people and 8 square feet for each additional person. What array area does that give a five-person Nevada household?

• A28 square feet
• B40 square feet
• C64 square feet
• D100 square feet

To limit collector overheating on a sunny, low-use day, FSEC/DOE practice keeps storage at about which ratio to collector area?

• A0.2 gallons of storage per square foot of collector
• BStorage volume equal to the drainback pot only
• C10 gallons of storage per square foot of collector
• D1.5 to 2 gallons of storage per square foot of collector

A south-facing roof is 25 degrees west of true south. For a residential glazed DHW array, FSEC-style orientation guidance says which of the following?

• AThe array is unusable and must be moved to a north wall
• BA modest west-of-south azimuth is usually acceptable; expect a small loss versus true sou…
• CThe array must be laid flat to cancel the azimuth error
• DThe license requires magnetic south, so 25 degrees is a code violation

When siting potable solar collectors, the designer should keep the array free of shade during which solar-time window?

• AMidnight to 2 a.m. only
• BSunset only, because morning sun is unused
• CAbout 9 a.m. to 3 p.m., when most of the day's collectable energy arrives
• DShade is desirable so the collectors never stagnate

For a potable solar DHW system in a Nevada climate that sees hard freezes, which freeze-protection strategy is appropriate?

• AAn uninsulated open-loop array that relies on hope
• BA drainback or closed glycol collector loop designed to keep water from sitting in outdoo…
• CLeaving a hose bib dripping on the roof
• DFilling the collectors with swimming-pool water in October

Why might a Las Vegas open-loop ICS water heater be a poor copy-paste design for a Reno house?

• AReno is south of Las Vegas, so collectors must face north
• BReno has a much more serious freeze climate; an integral collector-storage unit on the ro…
• CThe 2018 UPC bans all ICS systems statewide
• DReno forbids backup water heaters

A thermosiphon solar water heater circulates without a pump. Where must the storage tank sit relative to the collectors?

• ABelow the collectors so the hot water can fall
• BAbove the collectors so heated water can rise into the tank
• COn a north wall, regardless of collector height
• DInside the swimming-pool equipment pad

Why does a solar DHW storage tank usually need a mixing valve even if every shower has an ASSE 1016 valve?

• ASolar tanks commonly store water well above 120°F, and a source mixer protects the whole…
• BThe 2018 UPC bans ASSE 1016 valves wherever solar is present
• CMixing valves increase collector stagnation temperature
• DA mixing valve replaces the tank T&P valve

Which listing is the usual standard for a master thermostatic mixing valve at a solar DHW tank outlet?

• AASSE 1017
• BASSE 1003 only
• CASSE 1013 reduced-pressure principle assembly only
• DASTM E84

A solar tank is stored at 160°F while fixtures must not exceed 120°F. What is the design reason for storing hotter than the delivery temperature?

• AHotter storage increases usable hot-water capacity after mixing and reduces Legionella ri…
• BThe UPC requires all tanks to be stored at 210°F
• CMixing valves cannot operate unless the tank is below 100°F
• DHotter storage eliminates the need for collector freeze protection

Per 2018 UPC Section 603.5.4, a heat exchanger used for solar heating must do which of the following?

• AProtect the potable water system from contamination by the heat-transfer medium
• BBe omitted whenever glycol is used
• CDischarge glycol directly into the house hot-water branches
• DReplace the storage-tank T&P valve

Ethylene glycol is used as the collector-loop fluid on a potable solar water heater. What heat-exchanger construction does UPC 603.5.4 require?

• ASingle-wall, because all glycols are food grade
• BA garden-hose connection between the loops
• CNo heat exchanger; pipe the ethylene glycol through the fixtures
• DDouble-wall construction with the space between the walls vented to the atmosphere