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100+ Free AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Practice Questions

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2026 Statistics

Key Facts: AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Exam

80 Questions

Official Question Count

PSI Candidate Information Bulletin

210 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-79 Air Conditioning and Refrigeration Including Solar Examination consists of 80 multiple-choice questions administered in a 210-minute open-book PSI session, plus a separate 30-question / 75-minute solar examination with a 70% passing threshold ($66 exam fee). This online practice bank provides 100 realistic practice questions with detailed code references and technical calculations.

Sample AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Practice Questions

Try these sample questions to test your AZ ROC C-79 Air Conditioning and Refrigeration Including Solar exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A commercial flat-plate solar thermal collector array receives an average solar irradiance of 300 BTU/h·ft². The collectors have a total surface area of 400 ft² and deliver heat to a fluid loop where the entering fluid temperature is 110°F, leaving temperature is 140°F, and flow rate is 4.8 GPM of pure water. What is the thermal efficiency of the solar collector array?
A.50.0%
B.60.0%
C.70.0%
D.80.0%
Explanation: Total solar energy incident on the collector array = 300 BTU/h·ft² × 400 ft² = 120,000 BTU/h. Thermal energy absorbed by the water loop is Q = GPM × 500 × ΔT = 4.8 × 500 × (140°F - 110°F) = 72,000 BTU/h. Thermal efficiency = (Useful Heat Collected / Incident Solar Energy) = (72,000 BTU/h / 120,000 BTU/h) × 100% = 60.0%.
2When calibrating a differential temperature controller for a solar thermal forced-circulation hydronic heating loop, what is the standard recommended collector-to-tank temperature differential (ΔT) to start the solar circulating pump (cut-in setpoint)?
A.2°F to 4°F
B.8°F to 20°F
C.30°F to 45°F
D.50°F to 65°F
Explanation: Differential temperature controllers are typically set for a cut-in ΔT of 8°F to 20°F (commonly 12°F to 16°F) between the collector sensor and storage tank sensor. This ensures the collector is hot enough to transfer net positive heat into the storage volume while overcoming pipe heat losses, without short-cycling the pump.
3An HVAC solar contractor is installing an active closed-loop solar thermal system in northern Arizona. What concentration of uninhibited or inhibited USP propylene glycol in water is required to provide freeze protection down to -28°F?
A.10% propylene glycol / 90% water
B.25% propylene glycol / 75% water
C.50% propylene glycol / 50% water
D.85% propylene glycol / 15% water
Explanation: A 50/50 volume mixture of propylene glycol and water provides burst protection down to -60°F and freeze protection down to approximately -28°F. Propylene glycol is non-toxic and preferred over ethylene glycol for systems with potential indirect domestic water heat exchange.
4During a summer power outage in Phoenix, Arizona, a high-efficiency glazed flat-plate solar collector array enters a stagnation condition (zero fluid circulation under full sunlight). What internal absorber temperature can these collectors reach?
A.160°F to 180°F
B.200°F to 220°F
C.350°F to 400°F
D.600°F to 750°F
Explanation: Glazed flat-plate collectors under full summer solar radiation in desert climates reach stagnation temperatures between 350°F and 400°F (evacuated tubes can exceed 450°F). Solar piping, valves, and expansion tanks must be rated for these extreme temperatures and pressures.
5A closed solar thermal collector loop contains 30 gallons of 50% propylene glycol solution. The system operates between a cold fill temperature of 60°F (fill pressure 30 psig) and a maximum operating temperature of 210°F (relief valve set at 75 psig). Given fluid thermal expansion of 5.5%, what is the minimum required total acceptance volume of the solar expansion tank?
A.0.85 gallons
B.1.65 gallons
C.3.50 gallons
D.6.20 gallons
Explanation: The liquid expansion volume is calculated by multiplying total loop fluid volume by the liquid expansion percentage: 30 gallons × 0.055 = 1.65 gallons. The expansion tank must have a liquid acceptance capacity of at least 1.65 gallons (plus safety margin for vapor displacement during stagnation).
6In a solar thermal drainback HVAC system, all solar piping between the outdoor roof collectors and the indoor drainback reservoir tank must be installed with a continuous downward slope. What is the minimum required pitch per foot of pipe run according to solar piping standards?
A.1/16 inch per foot
B.1/8 inch per foot
C.1/4 inch per foot
D.1/2 inch per foot
Explanation: Solar drainback systems depend entirely on gravity to drain fluid out of collectors and exposed outdoor lines whenever the pump stops. Standard installation requirements mandate a minimum downward pitch of 1/4 inch per foot (and no sags/traps) on all uninsulated and insulated solar lines.
7According to the International Mechanical Code (IMC) and Plumbing Code (IPC), when a solar thermal loop containing toxic chemical additives (such as ethylene glycol or chemical corrosion inhibitors) transfers heat to a potable water heating system, what type of heat exchanger MUST be used?
A.Single-wall heat exchanger with automatic water makeup
B.Double-wall heat exchanger with a vented intermediate air space
C.Direct immersion bare copper coil without separation
D.Counter-flow single-wall plate heat exchanger with check valves
Explanation: IMC Section 1403 and IPC mandate that heat exchangers transferring heat between non-potable toxic heat transfer fluids and potable water must be double-wall construction with an intermediate space vented to the atmosphere so leaks are visibly detected without contaminating potable water.
8Because solar water heating storage tanks can reach temperatures well in excess of 160°F on bright summer days, what device must be installed on the domestic hot water supply line leaving the solar storage tank to prevent scalding?
A.Pressure reducing valve (PRV)
B.ASSE 1017 thermostatic mixing valve
C.Temperature-actuated solenoid valve
D.Flow limiting orifice disc
Explanation: An ASSE 1017 thermostatic mixing valve (tempering valve) is required on solar water heating storage tanks to mix cold domestic supply water with superheated tank water, maintaining delivered hot water at a safe setpoint (typically 120°F) to prevent severe scalding.
9A solar-assisted absorption air conditioning system utilizes a single-effect lithium bromide-water (LiBr-H2O) absorption chiller. What minimum hot water generator fluid supply temperature is required from the solar collector array for effective chiller operation?
A.110°F to 125°F
B.170°F to 195°F
C.260°F to 300°F
D.400°F to 450°F
Explanation: Single-effect LiBr-H2O absorption chillers require generator firing hot water temperatures in the range of 170°F to 195°F (77°C to 90°C), which can be efficiently supplied by high-performance evacuated tube or advanced flat-plate solar collectors.
10Where should a microbubble air eliminator / air separator be installed in a closed-loop hydronic solar thermal system for optimum air removal performance?
A.At the lowest point of the system return line entering the storage tank
B.At the point of highest fluid temperature and lowest pressure (suction side of pump)
C.On the high-pressure discharge piping leaving the circulator pump
D.Inside the expansion tank bladder connection
Explanation: Air separators remove entrained air most effectively where fluid solubility is lowest—which occurs at the highest temperature and lowest pressure point in the loop (on the supply side coming from collectors, right before the circulator pump suction).

About the AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Exam

The Arizona ROC C-79/CR-79/R-39 Air Conditioning and Refrigeration Including Solar Examination is a computer-delivered, open-book trade examination administered by PSI Services LLC for the Arizona Registrar of Contractors. The exam tests comprehensive technical knowledge across commercial and residential HVAC-R systems with specialized emphasis on solar thermal energy collectors, solar-assisted heating and absorption/chilled water cooling, hydronics, EPA Section 608 compliance, IMC/IFGC code compliance, electrical controls, testing and balancing, and OSHA 1926 jobsite safety.

Assessment

Two separately scored PSI examinations, both open book and both requiring 70%: the main trade examination (80 questions / 210 minutes) and the solar examination (30 questions / 75 minutes). Solar content outline: Collection Loops (5), Components (4), Installation (5), Maintenance (2), Mounting (4), Principles (5), Solar Systems Piping (5).

Time Limit

210 minutes

Passing Score

70%

Exam Fee

$66 (Arizona ROC / PSI Services LLC)

AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Exam Content Outline

15%

Refrigeration

12 of 80 items on the official PSI content outline. Refrigeration cycle, components, refrigerants, charging and recovery.

15%

Air Conditioning

12 of 80 items on the official PSI content outline. Comfort cooling equipment, heat pumps, airflow and system performance.

15%

Warm Air Heating

12 of 80 items on the official PSI content outline. Gas-fired furnaces, space heaters, heat exchangers and combustion.

10%

Controls and Motors

8 of 80 items on the official PSI content outline. Thermostats, pneumatic and electrical controls, motors and drives.

6%

Fuel Piping Systems

5 of 80 items on the official PSI content outline. Liquid fuel and gas piping from the service connection to the equipment.

6%

Water Piping Systems

5 of 80 items on the official PSI content outline. Water piping, pumps, valves and condensate management.

6%

Steam, Hot, Chilled and Condensing Water

5 of 80 items on the official PSI content outline. Hydronic and chilled-water distribution within classification limits.

6%

Testing, Balancing, and Inspection

5 of 80 items on the official PSI content outline. Testing and balancing of refrigerant, heating, cooling and air-handling systems.

5%

Boilers

4 of 80 items on the official PSI content outline. Wet heating systems limited to 30 psig / 220 degrees F hot water and 15 psig steam.

5%

Ventilation

4 of 80 items on the official PSI content outline. Duct work, air filtering devices, water treatment devices and control piping.

5%

Evaporative Coolers

4 of 80 items on the official PSI content outline. Direct and indirect evaporative cooling units and water distribution.

5%

Sizing and Estimating

4 of 80 items on the official PSI content outline. Load calculation, equipment sizing and material estimating.

How to Pass the AZ ROC C-79 Air Conditioning and Refrigeration Including Solar Exam

What You Need to Know

  • Passing score: 70%
  • Assessment: Two separately scored PSI examinations, both open book and both requiring 70%: the main trade examination (80 questions / 210 minutes) and the solar examination (30 questions / 75 minutes). Solar content outline: Collection Loops (5), Components (4), Installation (5), Maintenance (2), Mounting (4), Principles (5), Solar Systems Piping (5).
  • Time limit: 210 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-79 Air Conditioning and Refrigeration Including Solar Study Tips from Top Performers

1Master solar thermal HVAC loop dynamics including differential temperature controller setpoints (cut-in/cut-out), glycol thermal degradation, drainback systems, and expansion tank sizing formulas.
2Review superheat and subcooling calculations, EPA Section 608 recovery levels, vacuum evacuation standards (500 microns), and A2L mild flammability refrigerant handling safety.
3Practice psychrometric process calculations (sensible, latent, and total heat formulas) and fan laws scaling for CFM, static pressure, and motor horsepower.
4Understand hydronic circulation pump head calculations, pipe sizing, backflow prevention (RPZ valves), and boiler safety controls per ASME standards.
5Study OSHA 1926 fall protection rules (6-foot trigger height, 5,000 lb anchor points) and roof clearance requirements under IMC Chapter 3.

Frequently Asked Questions

How many questions are on the official Arizona ROC C-79/CR-79/R-39 Air Conditioning & Refrigeration Including Solar exam?

The official PSI R-39 / C-79 (CR-79) content outline lists 80 questions with 210 minutes allowed, plus a separate solar examination of 30 questions with 75 minutes allowed.

What passing score is required for the AZ ROC C-79 HVAC-R and Solar exam?

A minimum passing score of 70% is required on each examination: 56 correct out of 80 on the trade portion and 21 correct out of 30 on the solar portion.

Is the Arizona ROC C-79 trade exam open book?

Yes, the trade examination is open-book. Approved reference books such as the International Mechanical Code (IMC), Uniform Mechanical Code (UMC), NFPA 54, Solar Water Heating standards, and OSHA 1926 may be used during the PSI computer testing session.

What license classifications are covered by this trade examination?

This trade exam satisfies the trade examination requirement for commercial (C-79), dual commercial/residential (CR-79), and residential (R-39) air conditioning, refrigeration, and solar thermal HVAC integration licenses in Arizona.

Where can I register for the Arizona ROC C-79 exam?

Registration and test scheduling are administered online through PSI Services LLC at https://test-takers.psiexams.com/azcon or by contacting PSI candidate services.