REFRIGERATING REFRIGERATING ENGINEER
1. A method of reducing capacity c apacity without reducing compressor speed is called: A. low-pressure bypassing B. high- pressure bypassing C. hot-gas bypassing D. short-cycling 2. The thermal expansion valve responds to the: A. amount of superheat in the vapor leaving the coil B. amount of superheat in the liquid C. temperature in the evaporator coils D. pressure in the evaporator coils 3. The bulb for the thermal expansion e xpansion valve is located: A. in the middle of the evaporator coils B. near the evaporator coils outlet C. near the evaporator coils inlet D. on the bottom row of evaporator coils 4. Thermostat is a: A. temperature-operated switch B. pressure-operated switch C. superheat-operated switch D. back-pressure-operated switch 5. The elements of a thermostat switch are usually of the: A. diaphragm type C. valve type B. bimetal type D. pilot-valve type 6. When heavy electrical currents are involved, the thermostat will be operated by a: A. small circuit breaker C. fusetron B. pressure pipe D. relay 7. If the compressor runs continually, the c ause might be the: A. high-pressure cutout switch is jammed open B. low-pressure switch is jammed shut C. thermal bulb is not operating properly D. scale trap is clogged 8. The solenoid valve can be typed as a: A. thermal valve C. bellows valve
B. magnetic magnetic stop valve D. bimetallic bimetallic valve 9. If the compressor has been running r unning satisfactorilly for a long period of time but the oil level can rise slowly, the thing to do would be to: A. drain without sufficient oil to bring it down to the proper running level B. shutdown the compressor and check the oil level with the machine stopped C. check the dehydrator cartridge D. check to see if there is too much refrigerant in the system 10. If the compressor had been running r unning satisfactorily for a long period of time but suddenly the compartment temperature started to rise, the trouble might be: A. the solenoid valve has jammed shut B. the expansion valve may have water frozen in it C. a refrigerant leak has developed D. Any of the above 11. When charging a Freon system, all the valves should be in their normal position except in the: A. expansion valve C. king valve (liquid) B. purge valve D. solenoid valve 12. Abnormal discharge temperatures would be caused by: A. leaky suction valves C. faulty piston rings B. leaky discharge valves D. any of the above above 13. A device for holding open the suction valve and drawing gas from the suction manifold and returning it to the suction line w ithout compressing it is called a: A. discharge line bypass C. suction line bypass B. cylinder unloader D. relief valve 14. As heat is removed from a substance it gets colder. When no more heat can be removed and the temperature cannot be lowered any further, we have reached: A. perfect zero C. absolute zero B. double zero D. cold zero
15. The boiling point of water in an open container at sea level is 212°F. If the pressure in the open container is decreased, such as going up to the top of a mountain, the boiling point will be: A. increased C. the same B. decreased D. none of the above 16. Another name for the liquid valve is the: A. master valve C. Freon valve B. king valve D. shutoff valve 17. If the temperature in the icebox is too high, the trouble could be: A. a clogged scale trap B. air in the system C. automatic controls not functioning properly D. insufficient cooling water to the condenser 18. Oil is added to a Freon compressor by: A. pouring through oil hole in base B. pumping in with a hand pump C. pumping in with an electric-driven pump D. shutting down the machine and pouring in through the crack-case inspection plate opening 19. If no gaskets are used in the piping joints of a Freon system, the joints must be is to: A. finished joints C. ground joints B. welded joints D. soldered joints 20. When adding oil to a Freon system one must be sure that: A. all air is removed from the pump and fittings B. there is not too high a suction pressure C. the discharge pressure is not too high D. the condenser is shutdown 21. If the head pressure is too high: A. the relief valve should open before t he highpressure cutout B. the relief valve should open and let excess refrigerant go to receiver C. the high-pressure cutout switch should operate before the relief valve opens D. close in on the suction valve
22. If the compressor-discharge temperature is higher than the receiver temperature: A. increase the amount of cooling water to the condenser B. decrease the amount of cooling water to the condenser C. add more refrigerant to the system D. remove some of the refrigerant from the system 23. The dehydrator is used: A. to remove moisture from the system B. to remove air from the system C. when adding refrigerant to the system D. A and C 24. If the discharge side of the thermal expansion valve is warmer than the inlet side, the: A. expansion valve is working normally B. expansion valve is not working normally C. solenoid is not working normally D. scale trap is dirty 25. The oil level in the compressor should be checked: A. while the compressor is in operation B. just before starting the compressor C. after a long period of operation D. B and C 26. The relief valve is located on the: A. discharge side of condenser B. discharge side of compressor C. outlet of the evaporator coils D. receiver tank 27. The expansion valve on a Freon system controls the: A. superheat of the gas leaving the c ompressor B. back pressure in the evaporator C. temperature of the icebox D. superheat of the gas leaving the evaporator 28. The scale trap is located betwee n the: A. king valve and the expansion valve B. solenoids valve and expansion valve C. evaporator and receiver
D. compressor and evaporator 29. If the high-pressure switch on the compressor opens and stops the compressor, a possible cause could be: A. too much cooling water going through t he condenser B. no enough refrigerant in the system C. a leak in the evaporator coils D. no enough cooling water going through the condenser 30. The capacity of the refrigerating unit can be regulated by: A. changing the speed of the compressor B. changing the amount of cooling water to the condenser C. changing the amount of the refrigerant in the system D. any of the above 31. Which of the following would not cause high suction pressure? A. insufficient refrigeration B. leaky suction valves C. expansion valve stuck open D. suction valve not adjusted properly 32. A device used to keep moisture from passing through the system is called a: A. humidifier C. dehydrator B. aerator D. trap 33. If a compressor runs continuously, the cause might be a: A. defective thermal valve B. clogged scale trap C. stuck high-pressure switch D. Stuck low-pressure switch 34. Dairy products should be kept at a temperature of: A. 10° to 20° C. 35° to 45° B. 20° to 30° D. 15° to 25° 35. The purpose of the expansion valve bypass is to: A. increased the efficiency of the plant
B. increased the capacity of the evaporator C. control the refrigerant to the evaporator in case the automatic valve fail D. bypass the compressor 36. Frost on the outside of the thermal expansion valve maybe caused by: A. air in the system C. moisture in the system B. too much superheat D. any of the above 37. The charging valve is located between the: A. king valve and expansion valve B. receiver and the condenser C. compressor and the receiver D. evaporator coils and the compressor 38. A high suction pressure and a cold crankcase indicate: A. air in the system B. leaky suction valves C. expansion valve open too wide D. B or C 39. A high temperature in the icebox could not be caused by: A. insufficient refrigerant B. air in the system C. expansion valve open too wide D. too much refrigerant in system 40. When securing a Freon system for repairs: A. pump down to 1 or 2 pounds pressure B. pump down to a slight vacuum C. pump down to 10 to 15 pounds pressure D. remove all refrigerant from system 41. The solenoid valve is located between the: A. scale trap and the thermal expansion valve B. thermal expansion valve and the evaporator C. king valve and the scale trap D. automatic and manual expansion valves 42. When starting s refrigerating system, always: A. vent the condenser B. vent the evaporator C. bypass the condenser D. none of the above
43. Before securing a compressor to do maintenance work on it, be sure to: A. have gas mask handy B. notify the captain C. make arrangements to have perishables taken care of D. A and C 44. 212°F is equal to: A. 106°C B. 110°C C. 100°F
D. 100°C
52. Too much oil in the compressor would: A. absorb too much refrigerant from the system B. damage the expansion valve C. cause leakage through the shaft seals D. deposit oil on the condenser tubes 53. The refrigerant with the lowest boiling point is: A. NH3 B.CO2 C. F12 D. F22
45. A good refrigerant should: A. have a low boiling point B. have a higher latent heat C. be able to be liquefied at normal sea-water temperatures D. all of the above
54. A ton of refrigeration is equal to the removal of: A. 288,000 BTU per 24 hrs B. 28,000 BTU per 24 hrs C. 28,800 BTU per 24 hrs D. 280,000 BTU per 24 hrs
46. 140°F is equivalent to: A. 50°C B. 60°C C. 40°C D. 55°C
55. Which of the following would cause a high suction pressure? A. expansion valve not open enough B. expansion valve open too wide C. king valve not open wide enough D. dirty dehydrator
47. 70°C is equivalent to: A. 150°F B. 160°F C. 158°F D. 155°F 48. Low suction pressure is caused by: A. air in the system B. leaky compressor suction valves C. solenoid valve not functioning properly D. expansion valve causing flooding back 49. The charging connection in a refrigerating system is located: A. before the receiver B. between the condenser and the receiver C. between the receiver and the king valve D. between the king valve and the solenoid valve 50. If there is too much Freon in the system: A. the compressor will short cycle B. the compressor will run continuously C. the safety valve will discharge D. it will mix with the oil in the crankcase 51. A refrigerating unit of 1 ton capacity can remove: A. 500 BTU’s per min C. 200 BTU’s per min B. 288 BTU’s per min D. 100 BTU’s per min
56. Which of the following would cause high head pressure? A. dirty dehydrator B. insufficient cooling water C. air in the condenser D. all of the above 57. Which of the following would cause low head pressure? A. too much cooling water B. insufficient refrigeration gas C. insufficient cooling water D. A and B 58. The principle of mechanical refrigeration is: A. the absorption of temperature under heat, pressure, compression, and expansion B. the compression of a liquid under temperature and expansion C. the absorption of heat under temperature, compression, pressure, and expansion D. the conversion of a liquid to a gas
59. The function of the expansion valve is to: A. change the high-pressure liquid to a lowpressure liquid B. regulate the amount of liquid refrigerant to the expansion coils C. change the gas refrigerant to a liquid D. shut off the flow of refrigerant to the condenser 60. The oil separator (trap) is located betwee n the: A. compressor discharge valve and the condenser B. condenser and the receiver C. receiver and the king valve D. receiver and the expansion valve 61. The purpose of the oil trap is: A. to remove oil from the charging tank B. to add oil to the compressor C. to remove oil from the refrigerating gas D. none of the above 62. The boiling point of the ammonia at atmospheric pressure is: A. -28° C. B. +28° C. C. +28°F. D. -28° F. 63. The boiling point of CO 2 at atmospheric pressure is: A. +110°F. B. -110°F. C.+110°C. D.-110°C 64. The boiling point of Freon at atmospheric pressure is: A. -22°F. B. +22°F. C.+22°C. D. -22°C. 65. The dehydrator is located between the: A. receiver and the king valve B. receiver and the expansion valve C. condenser and the king valve D. condenser and receiver 66. The purpose of the dehydrator is located between the: A. receiver and the king valve B. receiver and the expansion valve C. condenser and the king valve D. condenser and receiver
66. The purpose of the dehydrator is to: A. remove oil from the refrigerant B. add more refrigerant to the system C. remove moisture from the refrigerant D. remove moisture from the crankcase oil 67. Which of the following would you apply if a person got Freon on his eyes? A. soapy water C. clean water B. sterile mineral oil D. sodium bicarbonate 68. The thermal expansion valve is located between the: A. receiver and the king valve B. king valve and the solenoid valve C. solenoid valve and the evaporator coils D. charging valve and the solenoid valve 69. The thermal expansion valve: A. controls the amount of gas coming from the dehydrator B. maintains a constant superheat of gas leaving the evaporator coils C. controls the amount of gas going to the receiver D. removes trapped oil from the r efrigerant 70. Water in the refrigerant is liable to: A. freeze on the expansion valve seat and cut flow of the liquid refrigerant B. emulsify the oil in the compressor C. freeze in the king valve D. clog the oil trap 71. The purpose of the scale trap is to: A. control the amount of the scale g oing to the compressor B. remove insoluble gases from the re frigerant C. remove dirt, scale, and metal chips from the refrigerant D. dissolve scale and dirt in the system 72. A double-seated valve allows the valve to be: A. packed only in the closed position B. packed in wide open or closed position C. operated as suction or discharge valve
D. removed for replacement without shutting down
C. the CO2 will come out in liquid form D. pumped out with a suction pump
73. Sensible heat: A. can be measured with a thermometer B. cannot be measured with a thermometer C. changes in the receiver tank D. increases with the cold
80. How is a Freon system purged? A. the same as the ammonia system B. the same as the CO2 system C. back to the extra supply bottle D. with a reefer pump
74. The latent heat of fusion is the amount of heat required to convert: A. 2 lbs. of ice at 32°F to 1 lb. of ice at 32°F B. 1 lb. of ice at 32°F to 1 lb. of water at 32°F C. 1 lb. of ice at 32°F to 1 lb. of steam at 32°F D. 2 lbs. of ice at 32°F to 1 lb. of water at 32°F
81. The solenoid valve is: A. a pressure-controlled stop valve B. a Freon-controlled check valve C. a temperature-controlled stop valve D. none of the above
75. The latent heat vaporization of water is: A.144 BTU B. 940 BTU C. 970 BTU D. 288 BTU 76. The latent heat vaporization is the amount of heat required to convert: A. 1 lb. of water at 212°F to 1 lb. of steam at 212° F B. 1 lb. of water at 180°F to 1 lb. of steam at 180° F C. 2 lbs. of water at 212°F to 1 lb. of steam at 212° F D. 1 lb. of ice at 32°F to 1 lb. of steam at 212°F 77. Too high suction pressure could be caused by: A. expansion valve open too wide B. leaky suction valves C. expansion valve bulb not working properly D. any of the above 78. How is an ammonia system purged so t hat the operator will not be overcome by the fumes? A. into the atmospheric line B. into a bucket of water C. into a bucket of lube oil D. back into the compressor 79. How is a CO2 system purged? A. when CO2 comes out, frost will form on a piece of metal held near the outlet B. through the king valve
82. The latent heat of fusion of ice is: A. 144 BTU B. 188 BTU C. 940 BTU D. 500 BTU 83. Latent heat: A. can be measured with a thermometer B. can be measured with a pyrometer C. cannot be measured with a thermometer D. changes as the refrigerant cools 84. Absolute zero is: A. 970° below 0 on the Fahrenheit scale B. 460° below 0 on the Fahrenheit scale C. 144° below 0 on the Fahrenheit scale D. the same as 0 on the Centigrade scale 85. When the evaporator coils are located in the icebox, the system is unknown as a: A. direct system B. low-pressure system C. indirect system D. high-pressure system 86. The amount of CO 2 of Freon in a cylinder is measured by: A. pressure C. weight B. volume D. psi 87. An excessively high head pressure could be caused by: A. solenoid valve shutoff B. insufficient cooling water to the condenser coil
C. insufficient cooling water to the evaporator coil D. too much cooling water to the condenser 88. The solenoid valve is controlled by: A. the amount of liquid in the system B. the amount of gas In the system C. the temperature in the condenser D. the thermal switch operated by the icebox temperature 89. The purge valve is located: A. in the lowest part of the system B. in the highest part of the system C. on the receiver discharge D. on the evaporator coil 90. The system should be purged: A. while the system is operating B. while starting up the system C. after the system has been shut down for a few hours D. once a week 91. The function of the compressor is to: A. pulls the refrigerant gas through the system B. increase the pressure of the refrigerant C. discharge the refrigerant to the condenser D. all of the above 92. The expansion valve is located between the: A. receiver and evaporator B. evaporator and compressor C. compressor and condenser D. condenser and receiver 93. If frost forms on the cylinder, t he cause would be: A. expansion valve not open wide enough B. charging valve left open C. expansion valve open to wide D. dehydrator not working properly 94. Which of the following would cause high head pressure? A. icebox door left open B. Insufficient cooling water C.Too much cooling water
D. suction valve not open enough 95. The high pressure side of the system is sometimes referred to as the: A. suction side B. cold side C. hot side D. filling side 96. A ton of refrigeration is equal to the cooling effect of : A. 2000 lbs. of ice melting in 24 hours B. 2000 lbs. of ice melting in 12 hours C. 2000 lbs. of water being converted to ice D. 2240 lbs. of ice melting in 24 hours 97. The scale trap (liquid strainer) is located between the A. compressor and oil separator B. king (liquid ) valve and expansion valve C. expansion valve and evaporator coils D. evaporator coil and compressor 98. When there is a Freon leak, the halide torch will burn : A. orange B. blue C. white D. green 99. Which of the following could be used to check a leak in an ammonia system? A. litmus paper B. halide torch’ C. sulphur stick D. A and C 100. Valve and piping in an ammonia system are made of: A. iron B. Brass C. copper D. bronze 101. In an ammonia system, the oil gauge must be kept: A. closed except when checking oil level B. open at all times
C. closed when machine is shutdown D. open when machine is shutdown 102. Freon is : A. colorless B. odorless C. nonpoisonous D. All of the above 103. Which of the following gasket materials should be used on a Freon system? A. Metallic B. asbestos C. rubber D. A and B 104. A double pipe condenser has: A. two piping systems side by side, one with cooling water one with refrigerant B. a small pipe inside a larger pipe, the cooling water passing through the small pipe and the refrigerant through the large pipe. C. two pipes for cooling water and one for the refrigerant D. none of the above 105. air can be prevented from getting into the system by: A. keeping all glands and stuffing boxes on the high pressure side type B. keeping the dehydrator clean at all times C. keeping all glands and stuffing boxes on the low pressure side type D. running the refrigerant to an aerator 106. the agent used in an indirect reefer system is: A. sodium chloride B. potassium chloride C. calcium chloride D. A and C 107. An Ammonia leak will turn litmus paper : A. blue B. red C. green D. yellow
108. A sulphur stick burning in the presence of ammonia will give off a : A. dense yellow smoke B. dense whit smoke C. dense red smoke D. dense green smoke 109. If the compressor were to run continuously without lowering the temperature, the trouble would probably be: A. insufficient refrigerant in the system. B. leaks C. leaky discharge valve D. any of the above 110. Ammonia leaks in the condenser can be detected by: A. smelling the discharge water B. applying litmus paper to the circulating water discharge C. adding oil of peppermint to the system and tracing the smell D. applying a soapy mixture to the condenser heads and looking for bubbles 111. When purging an ammonia condenser into a bucket of water, one can tell when the air is out and ammonia starts to come through by the: A. smell of ammonia being liberated from the water B. color of the water turning green C. color of the water turning bluish D. change of the bubbling sound of air to the crackling sounds of ammonia 112. Large leaks in a Freon system cannot always be detected with halide torch because it changes color with the slightest amount of Freon present. A large leak can be detected easier by applying A. sheets of litmus paper to all joints and watch for the color change B. a soapsuds solutions, mix with a little glycerine to hold the solutions together, and watch for the bubbles C. a thin layer of mineral oil to all joints and watch for bubbles
D. a lighted candle at the joints and watching for leaky spots blowing candle flame 113. When the evaporator coils are located in a brine solution and the brine is pumped through the icebox, the system is known as: A. a direct system B. an indirect system C. a low-pressure system D. a double-evaporator system 114. Obstruction of the expansion valve is usually caused by: A. congealed oil in the system B. scale C. water in the system D. all of the above 115. Too low suction pressure could be caused by: A. dirty scale traps B. shortage of refrigerant gas C. too much oil in the system D. any of the above 116. If an electrically operated compressor failed to start, the cause might be: A. an open switch B. a blown fuse C. burned-out holding coils in solenoid valve D. any of the above 117. The oil separator is located between the: A. evaporator and the compressor B. compressor and the condenser C. condenser and the dehydrator D. solenoid valve and the thermal expansion valve 118. To help a person who had been overexposed to ammonia gas, one would: A. apply artificial respiration B. wrap in warm blankets C. apply could compresses D. douse with cold water 119. If the compressor short-cycles on t he lowpressure cutout, the trouble might be:
A. lack of refrigerant B. dirty traps and strainers C. too much frost on coils D. any of the above 120. Ammonia will corrode: A. copper B. bronze C. brass D. all of the above 121. The dehydrating agent in Freon system is usually: A. slaked lime C. activated alumina B. sodium chloride D. calcium chloride 122. If any of the electrically contr olled devices in a Freon system malfunction, which of the following valves will also automatically shut off? A. king valve B. expansion valve C. solenoid valve D. condenser cooling-water inlet valve 123. Many pressure gages on a Freon system have two dials or graduations on one gage. The two dials represent: A. pressure and temperature B. liquid pressure and gas pressure C. suction and discharge pressure D. cooling-water inlet and outlet temperatures 124. A leaky discharge valve can usually be detected by: A. a fluctuating high-pressure gage B. a drop in icebox temperatures C. a discharge pressure lower than normal D. any of the above 125. The suction pressure in a Freo n system should be: A. the pressure which corresponds with a temperature about 20°F. below the temperature of the icebox B. the pressure which corresponds with a temperature equal to the temperature of the icebox C. the pressure which corresponds with a temperature about 20° above the temperature of the icebox D. none of the above
