Exam Prep – RETA CIRO 2025 Test, Exams of Refrigeration and Air Conditioning

Download Exam Prep – RETA CIRO 2025 Test and more Exams Refrigeration and Air Conditioning in PDF only on Docsity!

Exam Prep – RETA CIRO 2025 Test

Exam Prep - RETA CIRO 2025 Test | is the purpose of an SOP? - CO. specific slops necessary Lo safoly operale the system. Where can a list of the proper PPE needed to safely perform a job task be found? - CORRECT ANSWER-SOPs and MPs Which of the following requires hot work permits? - CORRECT ANSWEROSHA regulations What can be caused by trapped liquid? - CORR’ ANSWER-A possible release How much can the pressure of trapped liquid increase per degree sen 100 and 159 psi When working on an ammonia refrigeration system, which of the following has the responsibility to use the proper PPE? - CO. ANSWER-The technician or operator OSHA regulations require persons wearing respiratory protective equipment to have - CORRECT ANSWEF-a medical evaluation to confirin filness to wear the PPE. Lockout/Tagout required - CO. hazardous energy Which of the following is responsible to determine if an area is considered confined space? ~The owner/employer Fire watchers must be trained in- CORRECT ANSWER-the use of fu equipment. confirm that the energy source has indeed been made safe. During an are flash event, what is the conductor? - CORRECT ANSWER-The air A\s anare Mash fanlt contimics, the are flash explosion expansion is estimated Lo be how large? - CO. ANSWER-A0,000 21 What is the purpose of a refrigeration system? - CORRECT ANSWER-To maintain a temperature Operators must keep refrigeration systems operating safely and efficiently. Which of the following best describes lhe arcas of required knowledge [or this to be possible? - CORRECT ANSWER Basic physical principles, interpretation of information from temperature and pressure gauges, basic operating principles. Mechanical refrigeration is a series of steps that energy from a space or object to an area where it can do no harm. to an objecL at a lower Lemper Pressure is a measure of - CORRECT over a given area. What is the relationship between temperature difference and heat flow? - C ANSWER-The greater the temperature difference, the more rapid the heat flows. Specific heat - CORRECT ANSWER-is greater if the substance requires more heat energy to increas: Temperature is a measure of - CORRE: an object. If the force acting on an area of 5 square inches is 150 1b., what is the pressure on the atoa?- CORR ER-30 1b.fin? Using the vapor pressure curve for ammonia, 70° F cquals approximately what. valuc? - CORRECT ANSWER-114 psig Thirty-two psia equals - CORR’ The pressure midway between 0 psia and 0 psig is- CORRECT ANSWER-7.35 psia Which of the answers below is an example of heat transfer by conduction? - CORRECT A rod heated on one end becoming warm at the other end. If specific heat for air is .24 BTUb./" F and the specific volume is 12.7 cu. ft.b., how much heat energy must be removed to cool the air ina 15X12 x 8=1596 room that is 16'x 12’ x 8’ from 70" F to 40" F?- CORRECT ANSWER-870.8 BTUs Agallon of milk weighs 8 pounds. If it leaves the cow at 90° F and must be cooled to 35° F, how many BTUs must be removed in the cooling process? - CORRECT ANSWERA09.2 btu A meat plant processes 100 animals a day with an average processed weight of 730 pounds of beef per animals. The meat must be cooled to 45° from 85° . ANSWER2,205,000 A vapor can NOT be - CORRECT ANSWER-Subcooled What kind of a measure is a ton of refrigeration? - CORRECT ANSWER-A rate of heat transfer in BTUs per unit of time. cannot be created or destroyed. -40" F is equal to- CORRECT ANSWER-40° © Flash gas is- CORRECT ANS What are the four necessary components of a mechanical refrigeration system? - CORRECT ANSWER-Expansion device, evaporator, compressor, condenser A conventional mechanical refrigeration system is considered - C closed loop system Superheat is found at which points ofa typical system? - CORRECT ANSWER The compressor suction and compressor discharge line. Which of the following is NOT a truce statement about heal of compression? - CORRECT siency of most systems by improving the condensing rate. In an operaling ammonia refrigeralion system, subcooled refrigerant can only be a - g ‘ANSWER-liquid Superheated refrigerant can only be Calculate the compression ratio for the R22 system: (1) saturated suction pressure is 20 psig, (2) saturated discharge pressure is 175 psig, and (3) motor amps are 154. - CORRECT ANSWER3.46:1 ANSWER-A pressure difference What is one advantage to having evaporator pressures higher than atmospheric pressure? - CORRECT ANSWER Higher pressures keep air out of the system What are two refrigerants that are blended to create a new refrigerant with its own properties called? - C ‘ERA zeotrope or an azeotrope Discharge temperature should not be so high it- CORRECT ANSWERCauses Ling oil breakdown of the compressor Llubric: What factor do you multiply the mass flow rate (bs./min.) by to dclermine the vapor Mow rate through the compressor? - CORRECT. Three factors to consider when choosing a refrigerant are - CORRECT ANSWERCost, availability, and safety How much does the pressure of trapped ammonia liqnid change? - C 100 to 150 PSI per degree Fahrenheit increase What is one positive characteristic of most halocarbon refrigerants? - ANSWER-They are not generally flammable. Which is NOT a direct symptom of air in an ammonia system? - CORRECT ANSWER- Decreased evaporating temperature Of the refrigerants listed below, which refrigerant has the highest mass flow requirement at the same evaporator and condensing temperature? - CORRECT ANSWER-R-404a Which refrigerant was the first to be phased out by Montreal Protocol? - CORRECT CFC-12 As the ratio between the evaporator and condensing pressure increases, - CORRECT ANSWER-The theoretical discharge temperature Increases Under the Clean Air Act and Montreal Protocol, - CORRECT ANSWE-as long as a technician docs not perform work on portions of a s: frigorants, they do not need to be certified. Refrigerant leaks are detected using - CORRECT ANSWER either a sulfur stick on ammonia or electronic leak detector CFCs or HCFCs. A 300-ton refrigeration compressor operating at the conditions in Table Under the same operating conditions, which refrigerant listed below would operate with The primary reason for concern about HCFC-22 concentration in an engine room is - CORRECT ANSWER-oxygen deprivation A cartridge type gas mask may legally be used for personal protection from ammonia exposure when_- CORRE’ ER-the type of the hazard is known, and the concentration is known and is less than IDLH. The published lower explosive limit for ammonia is - CORRECT ANSWER-16% filled to 80% full of liquid Which of the following refrigeranls can be detected by ils odor even in low 7 concentrations? - CO) Which refrigerant would have the lowest condensing pressure at 95° F condensing - R-134a What is the pressure of an ammonia evaporator with a saturated temperature of 23° F?- CORRECT ANSWEN-38.87 psig What should the condensing pressure be at 92° condensing temperature in an ammonia system? - CORRECT ANSWER-171 47 psig An ammonia suction line has been calculated to have a volume of 7 cubic feet. How many pounds of saturated ammonia vapor at -30° F would this suction line contain? - CORRECT ANSWEF-0.37 pounds How many cubic feet of 30° F saturated ammonia vapor would result from vaporizing 65 pounds of saturated ammonia at 30° F?- CORRECT ANSWER-314 cubic feet An HCFC-22 liquid line has a volume of 0.1 cubic feet. How many pounds of saturated HCFC-22 liquid at 103° F will the line hold?- CORRECT ANSWER-10.57 pounds An HCFC-22 compressor is operating with a suction pressure of 30 psig. The suction temperature at 12° F. What is indicated? - CORRECT ANSWER-Suction vapor is 5° F superheated. Compare one cubic foot of HCFC-22 liquid at O° and at 100° . Which slatcment. is correct? - CORRECT ANSWER-HCFC-22 is lighter al 100° F than al. 0° F. What is the condilion of HCFC-22 vapor al-30" F and at 11 in. Hg. vacuum? - CORRECT ANSWER Superheated An HCFC-22 receiver contains both liquid and vapor. Non-condensables are not present. A pressure gauge on the receiver reads 220 psig. What is the temperature of the HCFC-22 in the vessel? - CORRECT ANSWER-108° F ANSWER-179.06 psig. Saturated liquid ammonia at 70° F weighs - CORRECT ANSWER-38.04 pounds per cubic foot. How much volume does 250 pounds of saturated liquid ammonia at 85° F occupy - CORRECT ANSWER-G.7 cubic ft ANSWER-To draw vapor away from the evaporator at the same rate it is being generated and to raise the pressure of that What is the of refrigeration compre: vapor to a point where it can be condensed. How does the refrigeration compressor maintain the temperature in the system evaporators? - { maintain the desired evaporating pressure. Discharge vapor from all compressors - CORRECT ANSWER-Will contain some level of superheat What is the basic idea behind the design of the hermetic compressor? - CORRECT ompressors than on Ling oil through the compression chamber. Double acting reciprocating compressors - C\ ‘k-compress vapor on the fore stroke and the back stroke How can an operator get thoroughly acquainted with an unfamiliar refrigeration plant? - CORRECT ANSWERBy studying the P & ID's and confirming them against the actual On a reciprocating compressor, a crankcase oil heater circuit is to be on when - CORRECT ANSWER-\he compressor is "OFF". When coming on duty, the operator should - acquaint themselves with all current operating conditions. Serious damage to the compressor and refrigerant loss. Slugging is caused by - CORRECT ANSWEF-oil or liquid refrigerant. The operator would be concerned about liquid slugging if they observed - CORRECT Oil in a screw compressor has four separate functions in refrigeration systems. They are - C ANSWERLubrication, sealing, cooling, cleaning. ANSWER-Oil is heavier than liquid ammonia. When a spring return ball valve is used in an oil drain, the operator needs to be sure of what condition? - CORRECT ANSWER-That the ball is vented sophisticated oil recovery systems are sometimes require for halocarbon refrigants beause oil and halocarbon refrigerants are - CORRECT ANSWER. soluble and quite miscible. Most oil separators for screw compressors are muli stage separators. The number of steps are - CORRECT ANSWER-4 Which of the following is not a use for oil? - CORR transfer in coils ANSWER-To improve heat ER-Reduee the oil smoke from the discharge gas Ina refrigeration system, oil is required for - CORRECT ANSWER Lubrication, cooling, sealing and cleaning Which of the following is not true about full internal force feed oil systems on reciprocating compressors? - CORRECT ANSWER-They use oil to lower the compressor discharge Lompore muly. SORRECT ANSWER-Provide the maximum heat transfer Gravity flooded evaporators - for a given evaporator size ANSWER-Results from densely stacked tubes Why are other secondary coolants preferred to water? - CORRECT ANSWER-They have lower freezing points. Which of the following expansion devices would not be used in a small refrigeration system? - CORRECT ANSWER-Hand expansion valve ANSWER-because they freeze products more quickly. What effect does the addition of fins to evaporator coils have? - Increases the efficiency of cvaporalors by increasing ils surface Depends on its specific heat Moisture contained in the air - CORRECT. the evaporator forming frost During hot gas defrost, - CORRECT. condenses in the evaporator The general direction of heat flow in a refrigeration system is- CORRECT ANSWER. heat energy reje ted in the condenser; heat energy gained in the compressor, Before the formation of liquid occurs in the condenser, the refrigerant vapor must be - CORRECT ANSWER Desuperheated Tn shell and tube condensers, - CORR! ANSWER -water circulates in the tubes and refrigerant vapor in the shell. What is the advantage of desuperhealing coils? - CORR! -ER-They reduce the discharge gas temperature entering the condenser. head pressure to increase.