100+ Free AZ ROC C-78/CR-78 Solar Plumbing Liquid Practice Questions

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Key Facts: AZ ROC C-78/CR-78 Solar Plumbing Liquid Exam

60 Questions

Official Question Count

PSI Candidate Information Bulletin

150 Minutes

Time Limit

PSI Candidate Information Bulletin

70%

Passing Score

Arizona Registrar of Contractors

$66

Exam Fee

PSI Services LLC

Open Book Computerized MCQ

Exam Format

PSI / AZ ROC Guidelines

100 Questions

Practice Question Bank

OpenExamPrep Practice Bank

The Arizona ROC C-78/CR-78 Solar Plumbing (Liquid Systems Only) Examination consists of 60 multiple-choice questions in a 150-minute open-book PSI session with a 70% passing grade ($66 fee). This online practice bank provides 100 realistic practice questions with thorough technical explanations.

Sample AZ ROC C-78/CR-78 Solar Plumbing Liquid Practice Questions

Try these sample questions to test your AZ ROC C-78/CR-78 Solar Plumbing Liquid exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the recommended fixed tilt angle for flat-plate solar thermal collectors installed in Phoenix, Arizona (approximate latitude 33.4° N) to optimize year-round domestic hot water performance?

A.15 degrees (Latitude minus 18 degrees)

B.33 degrees (Equal to local latitude)

C.48 degrees (Latitude plus 15 degrees)

D.60 degrees (Latitude plus 27 degrees)

Explanation: For year-round domestic hot water heating, fixed solar collectors should generally be tilted at an angle equal to the local site latitude (approximately 33° in Phoenix, AZ). This angle balances solar radiation capture across summer and winter seasons. Lower angles favor summer performance, while higher angles favor winter heating.

2To optimize a liquid solar thermal system specifically for winter performance in Arizona, what rule of thumb is applied to adjust the collector tilt angle relative to local latitude?

A.Subtract 15 degrees from local latitude

B.Add 15 degrees to local latitude

C.Multiply local latitude by 0.5

D.Set tilt angle to 90 degrees vertical

Explanation: Winter solar optimization requires tilting collectors steeper than the local latitude because the sun sits lower on the horizon during winter months. Adding 10° to 15° to the local latitude (Latitude + 15°) aligns the collector surface perpendicular to the low winter solar elevation angle.

3In the Northern Hemisphere, toward which true compass direction should fixed solar thermal collectors be oriented to capture maximum daily solar radiation?

A.True East (90 degrees azimuth)

B.True West (270 degrees azimuth)

C.True South (180 degrees azimuth)

D.Magnetic North (0 degrees azimuth)

Explanation: In the Northern Hemisphere, solar thermal collectors capture maximum solar radiation when oriented facing True South (180° true azimuth). Orienting facing true south ensures symmetrical solar collection before and after solar noon.

4When aligning solar collectors in Phoenix, Arizona using a magnetic compass, an installer must account for an approximate magnetic declination of 9° East. What compass reading corresponds to True South (180° true)?

A.171 degrees magnetic

B.189 degrees magnetic

C.180 degrees magnetic

D.195 degrees magnetic

Explanation: Magnetic declination is the angle between magnetic north and true north. With an easterly declination of 9° E in central Arizona, magnetic north points 9° east of true north. Therefore, True South (180° true) equals 180° - 9° = 171° on a standard magnetic compass.

5Which optical properties characterize a high-performance selective surface coating on a flat-plate solar collector absorber?

A.Low solar absorptance (α ≤ 0.20) and high thermal emittance (ε ≥ 0.90)

B.High solar absorptance (α ≥ 0.95) and low thermal emittance (ε ≤ 0.10)

C.High solar absorptance (α ≥ 0.95) and high thermal emittance (ε ≥ 0.90)

D.Low solar absorptance (α ≤ 0.20) and low thermal emittance (ε ≤ 0.10)

Explanation: A selective absorber surface (such as black chrome or titanium-nitride-oxide) is engineered to maximize shortwave solar absorption (alpha >= 0.95) while suppressing longwave infrared re-radiation losses (emittance epsilon <= 0.10), resulting in high thermal efficiency.

6In a heat-pipe evacuated tube collector array, how is heat transferred from the individual glass evacuated tubes to the solar fluid loop?

A.Solar loop fluid circulates directly inside each glass tube through plastic dip tubes

B.Vapor inside the copper heat pipe rises to a condenser bulb inserted into a dry manifold header bulb port

C.Evacuated tubes use air pumps to blow heated air across an external heat exchanger coil

D.Liquid refrigerant flows down an open gutter into the domestic water storage tank

Explanation: Heat-pipe evacuated tubes contain a sealed copper heat pipe with a small fluid charge. When heated by solar radiation, the internal fluid vaporizes and rises to the top condenser bulb. The bulb fits into a dry well inside the insulated manifold header, transferring heat to the solar loop fluid passing through the header without mixing fluids.

7According to standard roofing and building structural practices for solar thermal mounting, lag bolts securing mounting brackets into wood rafters must penetrate into the solid wood structural rafter by at least what minimum depth?

A.0.5 inches (13 mm)

B.1.0 inch (25 mm)

C.2.0 inches (51 mm)

D.4.5 inches (114 mm)

Explanation: To develop required withdrawal resistance against wind uplift per IBC/IRC and solar rack manufacturer guidelines, lag bolts must achieve a minimum penetration depth of 2.0 inches (or 1.5 to 2.5 inches depending on bolt diameter) into the center of solid wood framing members (rafters/trusses), excluding roof sheathing thickness.

8A solar water heating system consists of four 4' x 10' flat-plate collectors installed in parallel. If each collector requires a manufacturer-specified flow rate of 0.75 GPM, what is the required total flow rate for the collector array?

A.0.75 GPM

B.1.50 GPM

C.3.00 GPM

D.6.00 GPM

Explanation: In a parallel collector configuration, fluid flow splits equally among all collectors. The total system flow rate is the sum of the individual collector flow rates: Total GPM = 4 collectors × 0.75 GPM/collector = 3.00 GPM.

9Why is reverse-return piping preferred over direct-return piping in multi-collector solar thermal arrays?

A.It reduces total piping material length by 50 percent

B.It ensures equal pipe path length and equal fluid resistance through every collector

C.It allows domestic potable water to mix directly with toxic glycol loop fluid

D.It eliminates the requirement for an expansion tank in closed loops

Explanation: Reverse-return piping ensures that the total length of supply plus return piping connected to each collector is identical. This creates equal hydraulic pressure drop across all parallel collectors, self-balancing fluid flow without requiring manual balancing valves.

10When penetrating a shingle roof to install solar collector mounting standoffs, what is the proper method to ensure a long-term watertight seal per building codes?

A.Apply silicone sealant over top of the shingle surface after tightening the bolt

B.Install approved metal flashing slid beneath the upslope shingle course and sealed around the standoff

C.Wrap lag screws in duct tape prior to driving them into roof sheathing

D.Fill the rafter space below the penetration with expanding spray foam insulation

Explanation: Building codes and NRCA roofing standards require pre-engineered metal flashing plates layered properly under the course of shingles above the penetration (shingle-lap fashion). The standoff or lag bolt projects through a sealed boot collar on the flashing plate, preventing water intrusion.

About the AZ ROC C-78/CR-78 Solar Plumbing Liquid Exam

The Arizona ROC C-78/CR-78 Solar Plumbing, Liquid Systems Only Examination is a computer-delivered, open-book trade examination administered by PSI Services LLC for the Arizona Registrar of Contractors. The exam evaluates a candidate's technical knowledge in solar liquid thermal system design and installation, including solar collectors, closed-loop propylene glycol heat transfer loops, drainback systems, double-wall heat exchangers, solar storage tanks, differential temperature controllers, backflow prevention (ASSE 1013/1020), pipe sizing, and OSHA 1926 safety regulations.

Questions

60 scored questions

Time Limit

150 minutes

Passing Score

70%

Exam Fee

$66 (Arizona ROC / PSI Services LLC)

AZ ROC C-78/CR-78 Solar Plumbing Liquid Exam Content Outline

25%

General Plumbing

15 of 60 items on the official PSI content outline. Core plumbing practice supporting solar water heating tie-ins at existing stub-outs.

20%

System Designs

12 of 60 items on the official PSI content outline. Thermosyphon, direct open-loop and indirect closed-loop system layouts.

13%

Open and Closed Loop Systems

8 of 60 items on the official PSI content outline. Freeze protection, heat-transfer fluids, drainback and glycol loops.

13%

Pumps and Storage Systems

8 of 60 items on the official PSI content outline. Circulators, storage and expansion tanks, and heat exchangers.

12%

Pipes and Materials

7 of 60 items on the official PSI content outline. Piping, valves, insulation and material compatibility to 220 degrees F.

Collectors

5 of 60 items on the official PSI content outline. Collector types, orientation, tilt, mounting and array piping.

Controls

5 of 60 items on the official PSI content outline. Differential temperature controls, sensors and low-voltage wiring.

How to Pass the AZ ROC C-78/CR-78 Solar Plumbing Liquid Exam

What You Need to Know

Passing score: 70%
Exam length: 60 questions
Time limit: 150 minutes
Exam fee: $66

Keys to Passing

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

AZ ROC C-78/CR-78 Solar Plumbing Liquid Study Tips from Top Performers

1Master solar collector azimuth and tilt angle calculations for Arizona latitudes (typically latitude angle ± 15° for seasonal optimization).

2Understand double-wall heat exchanger rules under IPC/ISPC for separating non-potable heat transfer fluids (propylene glycol) from domestic drinking water.

3Know drainback solar system requirements: continuous 1/4 in. per foot unpitched slope toward the drainback reservoir and oversized unpressurized piping.

4Review ASSE 1017 thermostatic mixing valve rules requiring anti-scald temperature control (max 120°F) downstream of high-temperature solar storage tanks.

5Study OSHA 29 CFR 1926.501 fall protection requirements for 6-foot roof work and ladder safety ratios (4:1 pitch, 3-foot rail extension).

Frequently Asked Questions

How many questions are on the official Arizona ROC C-78/CR-78 Solar Plumbing exam?

The official PSI C-78 (CR-78) content outline lists 60 multiple-choice questions with 150 minutes allowed.

What passing score is required for the AZ ROC C-78/CR-78 exam?

A minimum score of 70% (42 correct out of 60 questions) is required to pass.

Is the Arizona ROC C-78/CR-78 exam open book?

Yes, approved references including the International Plumbing Code, Solar Energy Code, and solar thermal reference manuals may be brought into the PSI test center.

What Scope of Work does the C-78/CR-78 license cover?

The C-78 (Commercial) and CR-78 (Dual) license covers the installation, alteration, and repair of liquid-based solar thermal water heating systems and solar hydronic loops.

Where can I schedule the AZ ROC C-78/CR-78 exam?

Exams are scheduled through PSI Services LLC at https://test-takers.psiexams.com/azcon or by phone.

100+ Free AZ ROC C-78/CR-78 Solar Plumbing Liquid Practice Questions

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