Nevada C-37D Solar Pool Heating Contractor Examination

Under NAC 624.540(2)(d), which piping is within the Nevada C-37D Solar Pool Heating scope?

• APiping that connects solar collectors and heat exchangers used to heat a pool or spa with…
• BThe pool's main-drain, skimmer, and return-jet circulation plumbing
• CPotable fixture branches to lavatories and showers
• DPhotovoltaic DC homeruns from modules to an inverter

What piping material is the usual choice for an unglazed solar-pool collector loop that circulates filtered pool water at about 80°F?

• ASchedule 40 PVC listed for the temperature and pressure of the pool-solar loop
• BType M DWV copper used for waste stacks
• CUnlisted thin-wall automotive heater hose as the entire roof run
• DType K copper with 50/50 lead-tin waste solder

Why is Schedule 40 PVC acceptable on a typical unglazed solar-pool loop but not on a glazed potable-DHW collector loop?

• APool-solar water stays near 80°F, while a glazed DHW collector can stagnate well above PV…
• BPVC is listed only for natural-gas service
• CThe UPC bans all plastic pipe outdoors
• DPVC cannot be solvent-cemented

Where should the solar-collector feed tee be taken on an existing pool circulation system?

• AAfter the existing filter, so only filtered water enters the collectors
• BOn the suction line before the pump, so the pump never sees solar head
• COut of an unfiltered main-drain branch that C-37D newly installs
• DOut of the automatic chlorinator so chemicals precondition the panels

If the pool already has an automatic chlorinator, where does the solar-collector return rejoin the existing piping?

• AUpstream of the chlorinator so treated water is not pumped through the collectors
• BDownstream of the chlorinator so chlorine sterilizes the roof array
• CInto the pump suction so the chlorinator never sees solar flow
• DInto a new skimmer that the C-37D contractor installs

Outdoor Schedule 40 PVC solar-pool piping that is exposed to Nevada sun must be protected how?

• APainted or jacketed with a UV-resistant coating listed for outdoor PVC, or installed as U…
• BLeft bare because PVC is immune to ultraviolet light
• CWrapped only with ordinary fiberglass duct wrap and no jacket
• DCovered with interior latex wall paint

How must unglazed solar-pool feed and return piping be pitched on a drain-back system?

• AContinuously sloped so every collector and pipe segment drains by gravity when the pump s…
• BInstalled dead-level so water remains in the panels overnight
• CPitched toward the roof peak so air is trapped at the low points
• DRun uphill from the collectors to a sealed high point with no air inlet

Per 2018 UPC Table 313.3, horizontal PVC or ABS piping used on a solar-pool loop shall be supported at intervals not exceeding:

• A4 feet
• B32 inches
• C6 feet
• D12 feet

Per 2018 UPC Table 313.3, horizontal copper water tube 1-1/2 inches and smaller used on a solar-pool heat-exchanger loop shall be supported at intervals not exceeding:

• A6 feet
• B32 inches
• C4 feet
• D12 feet

Per 2018 UPC Section 609.4, a completed solar-pool water-piping section shall be tested how?

• AWith water at not less than working pressure, or (except plastic) 50 psi air, held not le…
• BWith 10 psi air for 5 minutes on every material including PVC
• CWith a 10-foot head of water for 15 minutes, the DWV test in UPC 712.2
• DBy visual inspection only; pressure tests are not required on solar piping

Per 2018 UPC Section 312.6, solar-pool piping installed in an unheated attic, crawl space, or exterior wall shall be:

• AProtected from freezing
• BExempt from freeze protection because Clark County rarely freezes
• CRequired to be Type M DWV copper
• DLeft uninsulated so it can freeze and relieve pressure

When several unglazed collectors are piped in a parallel bank, why is a reverse-return (first-in, last-out) header specified?

• AEvery flow path has the same equivalent length, so each panel receives nearly the same GPM
• BIt raises the outlet temperature of the last panel by running the panels in series
• CIt lets the installer omit isolation valves
• DIt converts the array into a closed glycol loop

How should unglazed solar-pool collectors almost always be piped to one another?

• AIn parallel, so each panel sees nearly the same cool inlet temperature
• BIn series, so water is heated 20°F in each successive panel
• CHalf the bank in series and half dead-headed
• DWith every panel on its own unfiltered suction line

Per FSEC-IN-23-83, where should the vacuum breaker on a self-draining solar-pool array be installed?

• ABetween the circulation pump and the collector array, at a point that stays above atmosph…
• BAt the highest point of the roof array so it can suck air while the pump is running
• COn the pump suction strainer so it breaks prime every time the pump starts
• DOn the automatic chlorinator so chemicals can drain into the attic

On a drain-back solar-pool system, how must check valves be arranged?

• ASo they cannot trap water in the collectors or block gravity drain-back when the pump sto…
• BOn every collector outlet, spring-loaded shut, so the roof stays full overnight
• COmitted entirely because check valves are never used on solar-pool systems
• DInstalled only on the potable house cold-water service

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

• ABe flashed and sealed so rain cannot enter the building
• BBe left as a raw oversize hole so the pipe can drain onto the deck
• CBe packed only with newspaper as a temporary wick
• DBe omitted by running the pipe through an unsealed ridge vent

A solar-pool array is designed for 42 GPM in the main feed. Which Schedule 40 PVC size is the usual FSEC/field choice for that flow?

• A2-inch, which is the common band for about 31 to 50 GPM
• B1/2-inch, which is reserved for sensor wells only
• C1-1/2-inch, which is typically limited to about 0 to 30 GPM
• D4-inch DWV, because drainage pipe has less friction

How are individual unglazed polypropylene panels usually joined to the roof headers?

• AWith manufacturer-listed flexible rubber couplings and clamps that allow thermal movement
• BWith rigid threaded steel nipples solvent-welded into the plastic header
• CWith 50/50 lead-tin soldered copper sweat joints
• DWith no joints; each panel is fusion-welded to the next in series

A two-story drain-back array has 28 feet of vertical return. Why does FSEC warn against putting the vacuum breaker at the roof peak?

• AThe return can be under negative static head, so a peak breaker admits air during normal…
• BA peak breaker is illegal under OSHA 1926 even if it never opens
• CVacuum breakers only work on potable cold-water tanks
• DThe peak is always above atmospheric pressure, so the breaker could never open to drain

FSEC-IN-23-83 notes that relocating the vacuum breaker onto the collector feed line can reduce required pump horsepower. Why?

• AFlow down the return can balance flow up the feed, so the pump no longer lifts the full s…
• BThe vacuum breaker becomes a second pump
• CIt lets the installer downsize from 2-inch pipe to 1/2-inch pipe
• DIt converts the open pool loop into a pressurized glycol loop

FSEC-IN-23-83 Figure 6.4 cautions that fluid velocities in solar-pool connecting pipe are not usually recommended above:

• A5 to 8 feet per second
• B0.5 feet per second
• C25 feet per second
• D50 feet per second

When C-37D uses a heat exchanger so collector fluid does not mix with pool water, which piping statement is correct?

• AThe exchanger and both of its connecting loops are in-scope C-37D work; the pool filter a…
• BThe exchanger may be omitted if the collector loop is tied into the house potable cold-wa…
• CC-37D must also rebuild the main drain and skimmer to feed the exchanger
• DA single-wall exchanger with ethylene glycol is required on every unglazed open-loop job

Which statement matches the official C-37D scope in NAC 624.540(2)(d)?

• ACollectors, piping, and heat exchangers used to heat swimming pools and spas with solar e…
• BSolar systems that heat potable domestic water, including house fixture branches
• CSolar systems that heat structures housing persons or animals, excluding pool equipment
• DCollectors, storage, and equipment used to convert solar energy into air-conditioning

A homeowner wants one contractor to add unglazed collectors on the pool and glazed collectors on the potable water heater. Under NAC 624.540, C-37D alone authorizes which portion?

• AThe pool collectors, their piping, and any pool heat exchanger only
• BThe potable DHW collectors and the house fixture branches
• CBoth the pool array and the potable DHW array
• DThe swimming-pool gunite shell and the new cartridge filter

In a typical unglazed solar-pool heating system, what serves as the thermal storage tank?

• AThe pool water itself
• BA separate 80-gallon potable solar tank in the garage
• CA drainback reservoir filled with ethylene glycol
• DThe automatic chlorinator body

Can one unglazed solar-pool array also be used as the household domestic-hot-water system?

• ANo. Unglazed pool collectors heat a large volume to about 80°F; DHW needs a much smaller…
• BYes, if a mixing valve is added at the kitchen sink
• CYes, because FSEC rates unglazed mats for 180°F potable service
• DYes, if the pool is cross-connected to the water-heater cold inlet

Per FSEC-EN-6-97, what pool-water temperature range is described as comfortable for a typical user in spring and fall?

• A78°F to 82°F
• B55°F to 60°F
• C104°F to 110°F
• D140°F to 160°F

What is the largest heat-loss path from an outdoor swimming pool?

• AEvaporation from the water surface
• BConduction through the shell into dry soil
• CRadiation from the underside of the diving board
• DSensible heat carried out the overflow by a 1/2-inch hose

Why does FSEC call a pool cover the best first step before, or along with, a solar array?

• AIt cuts evaporative heat loss and can raise water temperature about 5°F to 10°F depending…
• BIt replaces the need for any collector area
• CIt is required by UPC Table 313.3
• DIt converts unglazed collectors into glazed DHW collectors

For year-round solar-pool performance in the northern hemisphere, collectors should face which direction, and how far may they deviate?

• ADue south; up to 45° east or west of south does not significantly decrease performance if…
• BDue north; any southern exposure is wasted in Nevada
• CDue west only; morning sun cannot heat a pool
• DStraight up on a flat roof facing east is required

FSEC-EN-6-97 says flush-mounting unglazed pool collectors on a sloped roof, instead of standoff-tilting them to latitude plus 15°, typically costs how much winter performance?

• AOnly about 2 to 8 percent, which is seldom worth the extra mounting hardware
• BAbout 50 percent, so standoff tilt is mandatory
• CAbout 90 percent, so a flat roof cannot be used
• DZero in all cases, because tilt never matters

On a warm, sunny day when pool water is only a few degrees from air temperature, which collector type is more efficient per square foot?

• AAn unglazed low-temperature pool collector
• BA glazed medium-temperature DHW collector
• CAn evacuated-tube DHW collector aimed at 180°F
• DA photovoltaic module used as a thermal absorber

Per FSEC-EN-6-97, unglazed collector area as a fraction of pool surface is usually about which set of values?

• A100 percent in northern Florida, 80 percent in central Florida, and 65 percent in souther…
• B10 percent in every climate
• C200 percent in southern Florida and 25 percent in northern Florida
• DExactly one 4-by-12 panel regardless of pool size

A 16-foot by 32-foot outdoor pool is to be sized at FSEC's 80 percent collector-to-surface ratio. What collector area is required?

• AAbout 410 square feet
• B51 square feet
• C256 square feet
• D1,024 square feet

A 20-foot by 40-foot pool is sized at FSEC's 65 percent southern-climate ratio. What collector area is required?

• A520 square feet
• B80 square feet
• C260 square feet
• D1,300 square feet

An 18-foot by 36-foot pool in a cool, windy climate is sized at FSEC's 100 percent northern ratio. What collector area is required?

• A648 square feet
• B324 square feet
• C180 square feet
• D1,296 square feet

A 16-foot by 32-foot pool (512 ft²) is to be covered at 80 percent with 4-foot by 12-foot unglazed panels (48 ft² each). How many panels are required?

• A9 panels (432 ft², the first whole-panel count at or above 410 ft²)
• B2 panels
• C5 panels
• D18 panels

How does wind over an outdoor pool and an unglazed collector array change the heating load?

• AIt increases evaporative loss from the pool and convective loss from the unglazed collect…
• BIt always improves unglazed efficiency because moving air is warmer than the pool
• CIt has no effect on unglazed collectors because ASHRAE 96-80 already includes 25 mph wind
• DIt reduces the load so the array can be cut to 10 percent of the surface

On an FSEC/ASHRAE collector-efficiency graph, what is the fluid parameter plotted on the horizontal axis?

• A(Collector inlet temperature minus air temperature) divided by the solar irradiance on th…
• BPump horsepower divided by filter area
• CPool volume divided by turnover time
• DChlorine residual multiplied by pH

FSEC-IN-23-83 Case A is a 78°F pool, 75°F air, and 300 Btu/ft²-hr. About what unglazed-collector efficiency does Figure 5.1 show?

• A83 percent, higher than the glazed collector's about 70 percent on the same day
• B10 percent, because unglazed collectors cannot work above 70°F air
• C48 percent, the cool-cloudy Case B number
• D100 percent for the glazed collector and 0 percent for the unglazed collector

FSEC-IN-23-83 Case B is an 80°F pool, 65°F air, and 100 Btu/ft²-hr. What happens to the two collector types?

• AThe glazed collector is more efficient (about 60 percent vs. 48 percent), and a windy ung…
• BThe unglazed collector stays at 83 percent
• CBoth collectors reach 100 percent because the fluid parameter is negative
• DCollector type no longer matters because irradiance is zero

When calculating the net heating load of an outdoor pool, FSEC-IN-23-83 requires the designer to credit which daytime gain before sizing collectors?

• ADirect solar gain absorbed by the pool surface itself
• BHeat released by the automatic chlorinator
• CWaste heat from the service-panel transformer
• DThe full output of a glazed DHW array aimed at the house

Per FSEC-EN-6-97, about what water-temperature increase can a pool cover provide?

• AAbout 5°F when used 12 hours a day, and about 10°F when used 20 hours a day
• BAbout 1°F no matter how long it is left on
• CAbout 40°F in the first hour
• DNone; covers only keep leaves out

Which pool-cover strategy does FSEC-EN-6-97 recommend for a sunny climate?

• AA transparent or lightly translucent cover in the daytime so the pool still absorbs sun,…
• BAn opaque rubber roofing sheet left on all day so no sunlight reaches the water
• CNo cover, because covers always overheat unglazed collectors
• DA metal plate sealed to the waterline as a permanent lid

When is a glazed collector array a better C-37D choice than unglazed polypropylene?

• AA windy, cool-climate, or indoor pool that must be held well above ambient air temperature
• BAny Las Vegas backyard pool on a warm May afternoon
• CWhenever the owner also wants potable DHW from the same unglazed mats
• DWhenever the contractor does not want to slope the pipe for drain-back