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100+ Free AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation Practice Questions

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Key Facts: AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation 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-58/CR-58 Evaporative Cooling and Ventilating Examination consists of 60 multiple-choice questions administered in a 150-minute 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-58/CR-58 Evaporative Cooling & Ventilation Practice Questions

Try these sample questions to test your AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation 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 primary operational mechanism of a direct evaporative cooling system operating in dry desert climates?
A.Passing outdoor air over wetted media, causing water to evaporate into sensible heat, reducing air dry-bulb temperature while increasing specific humidity.
B.Circulating chilled water through a sealed closed coil without adding moisture to the supply airstream.
C.Compressing vapor refrigerant to absorb latent heat from outdoor air before discharging it into the space.
D.Utilizing chemical desiccants to absorb air moisture before passing the air through a secondary condenser coil.
Explanation: Direct evaporative cooling works through an adiabatic phase change process where sensible heat in the entering air evaporates water on wetted media. This converts sensible heat into latent heat, dropping the air dry-bulb temperature while increasing its specific humidity along a constant wet-bulb enthalpy line.
2When installing 12-inch thick rigid cellulose evaporative cooling media (CelDek), what is the maximum recommended face velocity to prevent water droplets from being entrained into the supply ductwork?
A.550 to 600 feet per minute (FPM)
B.250 to 300 feet per minute (FPM)
C.850 to 900 feet per minute (FPM)
D.1100 to 1200 feet per minute (FPM)
Explanation: Manufacturer guidelines and trade standards for 12-inch rigid cellulose media specify an optimum face velocity of 400 to 550 FPM, with a strict maximum limit of 550–600 FPM. Airflow velocities exceeding 600 FPM cause water carryover (blow-off), stripping droplets off the wet media face into the cabinet and duct system.
3How does an indirect evaporative cooling stage differ from a direct evaporative cooling stage in a two-stage (IDEC) HVAC system?
A.The indirect stage cools primary supply air sensibly through a heat exchanger without adding moisture to the supply air.
B.The indirect stage adds moisture directly to the supply air to achieve 100% relative humidity before entering the building.
C.The indirect stage uses electric heating elements to pre-warm outdoor air before passing over aspen pads.
D.The indirect stage relies on a mechanical compressor to chill water inside the sump basin.
Explanation: An indirect evaporative cooling stage uses a heat exchanger where secondary air is cooled evaporatively, chilling the heat exchanger plates/tubes. Primary supply air flows on the dry side of the exchanger, lowering its dry-bulb temperature sensibly without adding any moisture grains to the primary airstream.
4Why is a continuous water bleed-off assembly required on commercial evaporative cooler sumps operating in Arizona?
A.To drain mineral-concentrated water continuously, preventing dissolved scale (calcium/magnesium) from building up on media pads and sump walls.
B.To maintain constant high water pressure inside the distribution spider header.
C.To prevent the circulation pump motor from overheating by dumping excess water into the drain line.
D.To dilute the incoming electrical charge of the water pump motor.
Explanation: As pure water evaporates from the pads, minerals (total dissolved solids) remain in the sump. A continuous bleed-off line drains a small percentage of water (typically 1 to 3 GPH per 1,000 CFM depending on water hardness), preventing mineral concentration build-up and scaling on media pads.
5A commercial evaporative cooler delivers 10,000 CFM across 12-inch rigid cellulose media. Assuming a design requirement of 1.5 GPM of water flow per 1,000 CFM for thorough media flushing, what total pump flow rate is required?
A.15.0 GPM
B.7.5 GPM
C.22.5 GPM
D.30.0 GPM
Explanation: To calculate required pump capacity: Total GPM = (Total CFM / 1,000) * (GPM per 1,000 CFM). Here, (10,000 / 1,000) * 1.5 GPM = 10 * 1.5 = 15.0 GPM.
6What is the correct water level setting for a mechanical float valve inside an evaporative cooler sump basin?
A.1/2 inch to 1 inch below the top of the overflow pipe standpipe.
B.Flush with the top edge of the sump basin rim.
C.1/2 inch above the overflow pipe standpipe to ensure continuous overflow.
D.Completely covering the blower pulley and drive belt.
Explanation: The float valve arm should be adjusted so the shut-off water level is 1/2 to 1 inch below the overflow pipe opening. This prevents constant wasting of water through the overflow during normal pump operation while maintaining adequate sump volume.
7Which sequence of steps represents the proper end-of-season winterization procedure for an outdoor evaporative cooler in northern Arizona?
A.Shut off supply water valve, drain water supply line and sump, clean sump basin, disconnect pump power, and install seasonal weather cover.
B.Leave water supply on, add chemical antifreeze to the sump basin, and run the pump continuously through winter.
C.Close supply air dampers, seal the float valve open, and turn off only the blower breaker.
D.Disconnect the belt, fill the sump basin to the rim with oil, and cover the unit.
Explanation: Proper winterization requires isolating the water supply at a freeze-protected shutoff valve, draining all exposed piping and sump water to prevent freeze bursting, scrubbing scale from the sump, disconnecting electrical power to the pump/motor, and placing a protective canvas or metal cover over the unit.
8What condition occurs if aspen wood fiber media pads sag or slump inside an evaporative cooler pad frame?
A.Air bypasses through un-wetted voids at the top of the frame, delivering warm un-cooled outdoor air into the ductwork.
B.The static pressure drop across the media increases by 300%.
C.The water distribution spider header clogs automatically.
D.The blower wheel reverses rotation due to reduced drag.
Explanation: When aspen fiber pads age and slump downward inside their louver frames, gaps and voids form at the top. Outdoor air takes the path of least resistance through these un-wetted openings (air bypass), mixing uncooled hot outdoor air with supply air and severely degrading cooling performance.
9Why are rigid structured cellulose media blocks manufactured with unequal flute angles (such as 45-degree / 15-degree cross-fluted configurations)?
A.To direct water flow toward the air entering side, washing away dirt particles while directing air upward to maximize contact time without excessive pressure drop.
B.To prevent water from trickling down into the sump basin during operation.
C.To allow air to pass through at supersonic velocities without creating noise.
D.To eliminate the need for water distribution headers across the top of the media.
Explanation: Cross-fluted geometry (45° steep angle toward air intake, 15° shallow angle toward air exit) promotes self-cleaning action by pushing water toward the air-entering face. This flushes away airborne dust and debris while maintaining uniform air-water contact without high static resistance.
10What is the operating principle of a timed automatic sump dump valve / purge pump installed in a commercial evaporative cooler?
A.It periodically evacuates the entire mineral-laden sump basin every few hours of operation, refilling it with fresh supply water.
B.It injects liquid chlorine into the water distribution line every 15 minutes.
C.It pumps water out of the sump into the building supply ductwork during peak heat hours.
D.It reverses blower wheel rotation to blow scale off the media pads.
Explanation: An automatic sump purge system uses an electrical timer to energize a drain pump or solenoid dump valve every 6 to 12 hours. This dumps the entire contents of mineral-rich water out of the sump, allowing the float valve to refill the basin with fresh potable water, reducing scale formation.

About the AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation Exam

The Arizona ROC C-58/CR-58 Evaporative Cooling and Ventilating Examination is an open-book, computer-delivered trade examination administered by PSI Services LLC for the Arizona Registrar of Contractors. The exam tests comprehensive knowledge of direct and indirect evaporative cooling equipment, ventilation duct design, centrifugal blowers and fans, commercial kitchen exhaust systems (NFPA 96), psychrometric calculations, electrical motor wiring and controls, water supply and backflow prevention, and OSHA 1926 construction safety standards.

Questions

60 scored questions

Time Limit

150 minutes

Passing Score

70%

Exam Fee

$66 (Arizona ROC / PSI Services LLC)

AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation Exam Content Outline

25%

Warm Air Heating

15 of 60 items on the official PSI content outline. Gas-fired furnaces, space heaters, heat exchangers, burners and combustion air.

15%

Ventilation

9 of 60 items on the official PSI content outline. Supply and exhaust air, make-up air, air filtering devices and air balance.

13%

Piping and Tubing

8 of 60 items on the official PSI content outline. Water and gas piping from the service connection to the equipment served, plus control piping.

13%

Ducts and Insulation

8 of 60 items on the official PSI content outline. Duct layout, sealing, supports, and thermal and acoustical insulation.

10%

Controls and Motors

6 of 60 items on the official PSI content outline. Thermostats, pneumatic and electrical controls, blower motors and drives.

8%

Evaporative Cooling

5 of 60 items on the official PSI content outline. Direct and indirect evaporative units, pads, water distribution and bleed-off.

8%

Inspections and Testing

5 of 60 items on the official PSI content outline. Testing and balancing of air-handling systems and required inspections.

7%

Sizing and Estimating

4 of 60 items on the official PSI content outline. Load and airflow sizing plus material and labor estimating.

How to Pass the AZ ROC C-58/CR-58 Evaporative Cooling & Ventilation 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-58/CR-58 Evaporative Cooling & Ventilation Study Tips from Top Performers

1Master evaporative cooler sizing formulas, including calculating air exchange rates (e.g., 2-minute air change method for desert climates) and CFM airflow calculations.
2Understand psychrometric terms and formulas, including wet-bulb depression and direct evaporative cooling saturation efficiency calculations.
3Study fan laws and pulley sizing equations to calculate blower RPM, static pressure, and motor horsepower scaling.
4Review commercial ventilation standards, specifically NFPA 96 clearances to combustibles for Type I kitchen hoods, grease duct slopes, and make-up air interlocking.
5Memorize plumbing backflow requirements for water supply connections, ensuring minimum air gap rules and vacuum breaker heights per code.

Frequently Asked Questions

How many questions are on the official Arizona ROC C-58/CR-58 exam?

The official PSI C-58 (CR-58) content outline lists 60 multiple-choice questions with 150 minutes allowed.

What passing score is required for the AZ ROC C-58/CR-58 exam?

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

Is the Arizona ROC C-58/CR-58 Evaporative Cooling exam open book?

Yes, the trade examination is open-book. Approved references such as the International Mechanical Code (IMC), NFPA 96, ACCA Manuals, 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-58), dual trade (CR-58), and residential (R-58) evaporative cooling and ventilating contracting licenses in Arizona.

Where can I register for the Arizona ROC C-58/CR-58 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.