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100+ Free AZ ROC C-39 Air Conditioning and Refrigeration Practice Questions

Prepare for the Arizona ROC C-39/CR-39/R-39R Air Conditioning and Refrigeration Examination exam with instant access — no signup required.

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Key Facts: AZ ROC C-39 Air Conditioning and Refrigeration Exam

80 Questions

Official Question Count

PSI Candidate Information Bulletin

210 Minutes (3.5 Hours)

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-39 Air Conditioning and Refrigeration Examination consists of 80 scored multiple-choice questions administered in a 210-minute (3.5-hour) open-book PSI computer-delivered session with a 70% passing threshold ($66 exam fee). This online practice bank provides 100 realistic English-language practice questions with detailed code references and technical explanations adapted for exam preparation.

Sample AZ ROC C-39 Air Conditioning and Refrigeration Practice Questions

Try these sample questions to test your AZ ROC C-39 Air Conditioning and Refrigeration exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1An HVAC technician is troubleshooting an R-410A commercial split system. The liquid line gauge pressure reads 318 psig (corresponding to a saturated condensing temperature of 100°F), and the measured liquid line temperature at the outlet of the condenser coil is 88°F. What is the system subcooling, and what does this indicate if the manufacturer design subcooling is 12°F?
A.Subcooling is 6°F; the system is undercharged or has a metering valve over-feeding.
B.Subcooling is 12°F; the system subcooling matches manufacturer specification exactly.
C.Subcooling is 18°F; the system has a non-condensable gas or severe restriction.
D.Subcooling is 24°F; the condenser coil is severely fouled or overcharged.
Explanation: Liquid line subcooling is calculated by subtracting the measured liquid line temperature from the saturated condensing temperature obtained from the pressure-temperature (P-T) chart. Here, Subcooling = 100°F - 88°F = 12°F. Because 12°F matches the manufacturer's design subcooling target of 12°F exactly, the liquid line liquid seal is operating correctly.
2A walk-in cooler operating on R-404A has a suction pressure of 58 psig (saturated evaporator temperature of 25°F). The measured suction line temperature 6 inches downstream of the evaporator bulb attachment point is 41°F. What is the operating evaporator superheat?
A.8°F
B.16°F
C.24°F
D.33°F
Explanation: Evaporator superheat is calculated as the actual suction line temperature minus the saturated evaporator temperature corresponding to the low-side suction pressure. Superheat = 41°F - 25°F = 16°F. A superheat of 16°F is typical for commercial medium-temperature walk-in refrigeration units operating with thermostatic expansion valves.
3Under EPA Section 608 regulations, what level of evacuation must be achieved when disposing of or majorly servicing a high-pressure commercial appliance containing 250 lbs of R-134a using recovery equipment manufactured after November 15, 1993?
A.0 psig (atmospheric pressure)
B.4 inches of Hg vacuum
C.15 inches of Hg vacuum
D.10 inches of Hg vacuum
Explanation: Per EPA Section 608 (40 CFR Part 82, Subpart F), for medium/high-pressure appliances containing 200 lbs or more of refrigerant (such as R-134a, R-22, R-407C), recovery equipment manufactured after Nov 15, 1993 must evacuate the appliance to 10 inches of Hg vacuum before opening or disposing of the unit.
4When mounting a Thermostatic Expansion Valve (TEV) sensing bulb on a horizontal suction line with an outside diameter of 1-1/8 inches, what is the proper clock position for the bulb attachment?
A.At the 4 o'clock or 8 o'clock position
B.Directly on top of the pipe at the 12 o'clock position
C.Directly at the bottom of the pipe at the 6 o'clock position
D.Outside the insulated sleeve exposed to ambient air
Explanation: For suction line pipe diameters of 7/8 inch OD and larger (such as 1-1/8 inch), the TEV sensing bulb should be mounted at the 4 o'clock or 8 o'clock position (roughly 45 degrees below horizontal). This avoids sensing oil stagnant at the bottom of the pipe (6 o'clock) and vapor pockets at the top (12 o'clock), ensuring accurate vapor temperature feedback.
5What is the primary function of a compressor crankcase heater in a commercial air conditioning or refrigeration system?
A.To increase discharge gas superheat during normal compressor operation
B.To heat the suction gas prior to entering the compressor cylinders to boost volumetric efficiency
C.To prevent liquid refrigerant migration to compressor crankcase oil during the off-cycle
D.To melt ice accumulation on the compressor shell during low-ambient cooling
Explanation: During system off-cycles, liquid refrigerant naturally migrates to the coldest part of the system and dissolves into the compressor crankcase oil. Crankcase heaters keep the oil warmer than the rest of the system, vaporizing liquid refrigerant and preventing oil dilution, foaming, and compressor bearing wash-out upon startup.
6R-407C is a zeotropic blend (R-32/R-125/R-134a). When calculating superheat for a system operating with R-407C, which pressure-temperature curve value must be used?
A.Bubble point temperature from the P-T chart
B.Mean average temperature between bubble point and dew point
C.Dew point temperature from the P-T chart
D.Critical point temperature of R-134a
Explanation: Zeotropic refrigerant mixtures exhibit temperature glide. When calculating superheat, the dew point temperature (the temperature at which the last drop of liquid evaporates into superheated vapor) corresponding to the suction pressure must be used. When calculating subcooling, the bubble point temperature is used.
7Per EPA Section 608 regulations, what is the maximum allowable annual leak rate threshold for commercial refrigeration equipment containing 50 lbs or more of refrigerant before mandatory repair is required within 30 days?
A.20%
B.10%
C.30%
D.50%
Explanation: Under the EPA Section 608 leak repair regulations (effective 2019 updates), commercial refrigeration equipment containing 50 or more pounds of ozone-depleting or substitute refrigerant has an annual leak rate threshold of 20%. (Comfort cooling is 10%, industrial process refrigeration is 30%). If exceeded, repairs must be performed within 30 days.
8A commercial low-temperature walk-in freezer evaporator coil utilizes a 4,800 Watt electric defrost heater powered by a 208 Volt single-phase supply. What current draw should a technician read with a clamp-on ammeter when testing the defrost circuit?
A.11.5 Amps
B.17.3 Amps
C.23.1 Amps
D.38.4 Amps
Explanation: For a single-phase AC resistive load, Power (P) = Voltage (V) × Current (I). Therefore, Current (I) = P / V = 4,800 W / 208 V = 23.076 Amps, which rounds to 23.1 Amps.
9Where must an oil separator be installed in a commercial refrigeration system, and how does it return oil back to the compressor?
A.In the discharge line as close to the compressor as possible; oil is returned to the crankcase via a float-operated needle valve.
B.In the suction line before the accumulator; oil flows via gravity to the oil sump.
C.In the liquid line after the receiver; oil is pumped using a high-pressure auxiliary oil pump.
D.In the hot gas bypass line; oil returns during the defrost cycle only.
Explanation: Oil separators are installed in the compressor discharge line as close to the compressor outlet as practical. Hot discharge gas containing atomized oil enters the separator, where baffles or screens slow the velocity, allowing oil to drop to the bottom. When the oil level rises, an internal float mechanism opens a needle valve, returning oil directly to the compressor crankcase or oil reservoir.
10In an automatic pump-down refrigeration system, what component initiates the compressor shutoff sequence when room temperature is satisfied?
A.The high-pressure safety cutout switch
B.The evaporator defrost timer breaking power directly to the compressor contactor coil
C.The thermal overload protector inside the compressor motor windings
D.The room thermostat closing the liquid line solenoid valve, causing low-side pressure to drop until the low-pressure switch opens
Explanation: In an automatic pump-down system, when the room thermostat is satisfied, it de-energizes the liquid line solenoid valve (LLSV). The compressor continues to run, pumping remaining liquid refrigerant out of the evaporator into the receiver. When suction pressure drops to the low-pressure cutout setting, the low-pressure control opens, shutting off the compressor.

About the AZ ROC C-39 Air Conditioning and Refrigeration Exam

The Arizona ROC C-39/CR-39/R-39R Air Conditioning and Refrigeration 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 including refrigeration, air conditioning, warm air heating, electrical controls/motors, boilers, ventilation, evaporative cooling, fuel/water piping, steam/chilled water systems, TAB procedures, sizing/estimating, and OSHA 1926 safety regulations.

Questions

80 scored questions

Time Limit

210 minutes

Passing Score

70%

Exam Fee

$66 (Arizona ROC / PSI Services LLC)

AZ ROC C-39 Air Conditioning and Refrigeration Exam Content Outline

15%

Refrigeration

Vapor compression cycle, refrigerant types (HFCs, HFOs, natural refrigerants), recovery/recycling (EPA Section 608), superheat and subcooling calculations, expansion devices, evaporators, and commercial refrigeration controls.

15%

Air Conditioning

Split systems, packaged units, VRF/VRV systems, psychrometric chart analysis, sensible/latent heat loads, duct sizing (Equal Friction method), airflow measurement (CFM), and static pressure.

15%

Warm Air Heating

Gas furnaces, heat pumps, electric heating systems, heat exchanger inspections, combustion air requirements, venting (Category I-IV), limit switches, gas valves, and heating safety.

10%

Controls and Motors

Low-voltage control circuits (24V), line voltage wiring, contactors, relays, PSC/ECM motors, capacitors, thermostats, DDC automation, and electrical safety.

5%

Boilers

Low-pressure steam and hot water boilers, ASME code compliance, safety relief valves, low water cut-offs, expansion tanks, aquastats, and hydronic boiler controls.

5%

Ventilation

ASHRAE 62.1/62.2 standards, mechanical fresh air intake, kitchen exhaust hood systems (NFPA 96), ductwork design, fan laws, and indoor air quality (IAQ).

5%

Evaporative Coolers

Direct and indirect evaporative cooling systems, swamp cooler pumps, media pads, water sump maintenance, bleed-off valves, sizing, and desert climate application standards.

6.25%

Fuel Piping Systems

NFPA 54/IFGC natural gas and propane piping sizing, gas meter connections, pipe materials (black iron, CSST), leak testing, pressure drops, and shutoff valves.

6.25%

Water Piping Systems

Hydronic heating/cooling piping, copper, PEX, and steel pipe sizing, valve selection, backflow preventers, circulation pumps, and pressure drop calculations.

6.25%

Steam, Hot, Chilled, and Condensing Water

Chillers, cooling towers, steam traps, condensate return systems, glycol loop protection, thermal expansion, and water loop balancing.

6.25%

Testing, Balancing, and Inspections

TAB procedures, pitot tube traverse, velometer usage, hydronic flow meters, code inspection requirements, commissioning, and system troubleshooting.

5%

Sizing and Estimating

Manual J heating/cooling load calculations, Manual D duct design, equipment selection (Manual S), material take-offs, and project cost estimation.

How to Pass the AZ ROC C-39 Air Conditioning and Refrigeration Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 80 questions
  • 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-39 Air Conditioning and Refrigeration Study Tips from Top Performers

1Master superheat and subcooling diagnostic calculations, pressure-temperature (P-T) chart interpretation, and refrigerant recovery procedures per EPA Section 608.
2Review psychrometric principles including dry-bulb, wet-bulb, dew point, relative humidity, enthalpy, and sensible heat ratio calculations.
3Study gas furnace combustion air requirements (confined vs unconfined spaces) and Category I through IV flue venting rules per NFPA 54 / IFGC.
4Practice hydronic and steam system concepts, including expansion tank sizing, air elimination, low water cut-offs, and steam trap diagnostics.
5Memorize fan laws and pump laws to solve CFM, RPM, static pressure, GPM, and horsepower scaling problems rapidly during the timed exam.

Frequently Asked Questions

How many questions are on the official Arizona ROC C-39 Air Conditioning & Refrigeration exam?

The official PSI C-39/CR-39/R-39R exam contains 80 scored multiple-choice questions. Candidates are allotted 210 minutes (3.5 hours) to complete the exam.

What passing score is required for the AZ ROC C-39 exam?

A minimum passing score of 70% (56 correct answers out of 80 questions) is required to pass.

Is the Arizona ROC C-39 HVAC-R exam open book?

Yes, the trade examination is open-book. Approved references such as the International Mechanical Code (IMC), Uniform Mechanical Code (UMC), NFPA 54, Modern Refrigeration & Air Conditioning, and OSHA 1926 may be used during the PSI testing session.

What license classifications are covered by this trade examination?

This trade exam satisfies the trade examination requirement for commercial (C-39), dual trade (CR-39), and residential (R-39R) air conditioning and refrigeration contracting licenses in Arizona.

Where can I register for the Arizona ROC C-39 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.