Free NABCEP Solar Heating System Inspector Exam Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NABCEP Solar Heating System Inspector Exam practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1During a solar water heating inspection, a pump sends potable tank water through the collector and returns it to storage. Which system type does this describe?

   1. A. Indirect forced circulation
   2. B. Direct forced circulation
   3. C. Indirect thermosyphon circulation
   4. D. Closed-loop drainback circulation

   Answer: B

   Explanation: The guide states, "These systems are called direct, or open loop, because the collectors heat the potable water directly." In this system a pump circulates that potable tank water through the collector, identifying direct forced circulation.

   Reference: NABCEP Solar Heating Installer Resource Guide, v. 1.0 — Section 4.2.3, p. 36

2. 2A roof-mounted solar collector bank presents 32 square feet of projected area to an approved design uplift pressure of 30 pounds per square foot. What total uplift force should the inspector use when checking the building attachment design?

   1. A. 62 pounds of uplift
   2. B. 120 pounds of uplift
   3. C. 960 pounds of uplift
   4. D. 1,920 pounds of uplift

   Answer: C

   Explanation: The SHSI JTA directs inspectors to "Identify applications where design loads from the solar array may significantly impact structural integrity of the building." The specified design pressure acts across 32 square feet, so the load is 30 lb/ft² × 32 ft² = 960 lb. The other results add unlike quantities, use only one dimension, or double-count the bank.

   Reference: Solar Heating System Inspector Job Task Analysis Guide — Section II, Task 1.2, p. 5

3. 3On a solar collector loop, the weakest pressure-rated component is rated for 80 psi. Which of these relief-valve settings is the highest that meets the guide's component-rating rule?

   1. A. A 60 psi pressure relief setting
   2. B. A 75 psi pressure relief setting
   3. C. An 80 psi pressure relief setting
   4. D. A 90 psi pressure relief setting

   Answer: B

   Explanation: The guide states, "A suitable PRV must be rated below the pressure rating of each component in the system." Among the listed settings, 75 psi is the highest below the 80 psi limiting component; 80 psi is equal, and 90 psi exceeds it.

   Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.4, Install safety valves, guide p. 102

4. 4An inspector checks the standard temperature-and-pressure relief valve on a solar domestic water storage heater. At what pressure does the guide say the standard valve opens?

   1. A. At 100 psi
   2. B. At 125 psi
   3. C. At 150 psi
   4. D. At 175 psi

   Answer: C

   Explanation: The guide states, "The standard valve will release fluid, or pop off, at 210°F (99°C) and/or 150psi." The question asks for the pressure value, which is 150 psi.

   Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.4.3, Install system safety devices, guide p. 102

5. 5A solar collector temperature sensor is 90 feet from its differential controller, with no identified electrical noise. Which wire gauge does the NABCEP guide say is typically suitable at this length?

   1. A. 18-gauge thermostat wire
   2. B. 20-gauge thermostat wire
   3. C. 22-gauge thermostat wire
   4. D. 24-gauge thermostat wire

   Answer: A

   Explanation: The guide states, "Temperature sensors can typically be wired with 18-gage thermostat wire, unless the wire length exceeds 100 feet (30m) or the sensor wire could be subject to electrical noise." The stated 90-foot, low-noise run fits that guidance.

   Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.5.3, Install sensor wires, guide p. 110

6. 6An inspector traces a passive split thermosyphon loop after the sun heats the collector. What causes heat-transfer fluid to circulate toward the elevated tank?

   1. A. Water-main pressure through the collector loop
   2. B. A dedicated circulator in the collector loop
   3. C. Natural convection of warmer, lighter fluid
   4. D. A pump-driven siphon in the collector loop

   Answer: C

   Explanation: The guide states, "Thermosyphon systems use the natural convection of liquids to circulate the fluid through the collectors and storage tank." The elevated tank lets heated, less dense fluid rise without a dedicated circulator.

   Reference: NABCEP Solar Heating Installer Resource Guide, v. 1.0 — Section 4.2.1b, p. 34

7. 7An inspector assesses a tilted roof collector rack for wind uplift. At which rack feet do the most critical uplift loads usually occur?

   1. A. The rear feet of the tilted rack
   2. B. The front feet of the tilted rack
   3. C. The center feet of the tilted rack
   4. D. All feet equally on the tilted rack

   Answer: A

   Explanation: The guide states, "For most tilt rack configurations, uplift forces from wind will cause the most critical loads to occur at the rear feet of the rack." The inspector should focus on those rear attachments under the stated configuration.

   Reference: NABCEP Solar Heating Installer Resource Guide, v. 1.0 — Section 8.2.2a, p. 79

8. 8An inspector finds a cast-iron circulator body in a solar heating installation. In which loop would that material be consistent with the guide's pump-material distinction?

   1. A. The closed antifreeze collector loop
   2. B. The direct potable collector loop
   3. C. The potable side of an external exchanger
   4. D. The open domestic recirculation loop

   Answer: A

   Explanation: The guide says, "Cast iron pumps are used in closed loop systems, such as an Antifreeze system or some Drainback systems." It separately requires bronze or stainless steel for open loops carrying potable water. The stated closed antifreeze loop fits the cast-iron application.

   Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.4.2a, Pump materials, guide p. 98

9. 9A three-port thermostatic mixing valve combines hot storage water with cold supply water before fixtures. Which port should carry the temperature-controlled mixed water out of the valve?

   1. A. The cold inlet port
   2. B. The hot inlet port
   3. C. The mix outlet port
   4. D. The recirculation return port

   Answer: C

   Explanation: The guide states, "Two of the ports on the valve are connected to the cold water supply and the hot water supply from the storage tank or water heater. The third port is the outlet, or mix, port; its temperature is controlled by the valve." In the specified three-port valve, the mix outlet delivers tempered water; a recirculation-return connection belongs to a different valve arrangement.

   Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.4.3, Install system safety devices, guide p. 102

10. 10The collector sensor wire runs near line-voltage wiring, and its temperature readings are affected by electrical interference. Which wire construction does the guide recommend for this condition?

    1. A. Shielded sensor cable
    2. B. Unshielded twisted-pair cable
    3. C. Unshielded thermostat cable
    4. D. Unshielded single-conductor cable

    Answer: A

    Explanation: The guide states, "If electrical interference affects sensor readings, shielded sensor wire should be used." Shielding directly addresses the observed electrical noise; each alternative lacks shielding.

    Reference: NABCEP Solar Heating Installer Resource Guide — Section 8.5.3, Install sensor wires, guide p. 111