Assessment Test


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1. If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be an acceptable method of cleaning?

 
 
 
 

2. When checking zinc plates, or pencil Zincs in the refrigerating system condenser, what should you do?

 
 
 
 

3. What is true concerning the accumulation of air and other non-condensable gases in a refrigeration system?

 
 
 
 

4. Rather than design an infinite variety of thermostatic expansion valve sizes to accommodate different capacities for heat removal, some manufacturers use a few standard valve body sizes in conjunction with what other feature?

 
 
 
 

5. Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device?

 
 
 
 

6. Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter?

 
 
 
 

7. What is one function of the thermal expansion valve used in a refrigeration system?

 
 
 
 

8. When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will react in what way?

 
 
 
 

9. In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor?

 
 
 
 

10. A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporator superheat setting will result in which of the following?

 
 
 
 

11. When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb?

 
 
 
 

12. If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875" (2.21 cm) in diameter (considered small), the thermostatic expansion valve sensing bulb should be attached where on the return line?

 
 
 
 

13. Expansion valve maintenance should include which of the following procedures?

 
 
 
 

14. Which statement about calibrating a newly installed thermostatic expansion valve is correct?

 
 
 
 

15. Which of the installation steps listed is necessary for the proper operation of the thermostatic expansion valve?

 
 
 
 

16. What maintenance may be carried out on a thermostatic expansion valve?

 
 
 
 

17. When a thermostatic expansion valve is installed in a refrigerated container unit, the sensing bulb almost always requires insulation. Why is this so?

 
 
 
 

18. If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator?

 
 
 
 

19. If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result?

 
 
 
 

20. A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions?

 
 
 
 

21. An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom?

 
 
 
 

22. Vapor bubbles present in the liquid upon arrival to the thermal expansion valve in a refrigeration system may cause erosion of the expansion valve's needle and seat. This, in turn, could cause what condition?

 
 
 
 

23. Moisture entering a typical refrigeration system will most likely produce what effect?

 
 
 
 

24. Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true?

 
 
 
 

25. What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system?

 
 
 
 

26. Some 'hot gas' defrost systems reheat the refrigerant just prior to its returning to the compressor for what purpose?

 
 
 
 

27. The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs is to do what?

 
 
 
 

28. Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of accomplishing non-major repairs?

 
 
 
 

29. The pressure in the part of a high pressure refrigeration system about to be opened for a non-major repair should be brought to what value?

 
 
 
 

30. Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what?

 
 
 
 

31. What is the maximum volume to which refillable refrigeration cylinders should be filled?

 
 
 
 

32. When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should be done to compensate for or to correct this situation?

 
 
 
 

33. A box solenoid valve used in a refrigeration system should be installed in what manner?

 
 
 
 

34. When using nitrogen to pressure leak test a system, the nitrogen cylinder should always be equipped with what device or feature?

 
 
 
 

35. Which of the following statements is correct concerning the testing of an R-22 refrigeration system for leaks in an enclosed compartment with a halide torch?

 
 
 
 

36. If you find a refrigerant leak while using a halide torch, what will happen to the flame as the exploring tube approaches the leak?

 
 
 
 

37. In a refrigeration system, from what location would air and non-condensable gases be removed?

 
 
 
 

38. Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what action?

 
 
 
 

39. In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit?'

 
 
 
 

40. During normal operation, traditionally, how has most of the refrigerant released to the atmosphere from low pressure systems?

 
 
 
 

41. Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor?

 
 
 
 

42. Which of the fluids listed is suitable for use as a secondary refrigerant?

 
 
 
 

43. Alkylbenzene ISO 32 cSt synthetic refrigerant oil is miscible and suitable to use with which of the following refrigerants?

 
 
 
 

44. The amount of HCFC-123 in a storage cylinder is measured by what means?

 
 
 
 

45. Which of the following substances is normally classified as a low pressure refrigerant?

 
 
 
 

46. What is the color coding for a storage container of R-134a refrigerant?

 
 
 
 

47. The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmful effects ultraviolet radiation is called what?

 
 
 
 

48. The "tare weight" of a refrigerant storage cylinder refers to what weight?

 
 
 
 

49. The term 'oil foaming' in refrigeration practice, is used to describe what event?

 
 
 
 

50. What is the physical state and pressure condition of refrigerant as it enters the condenser of a typical refrigeration system?

 
 
 
 

51. What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration system?

 
 
 
 

52. What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system?

 
 
 
 

53. The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means?

 
 
 
 

54. A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is called what?

 
 
 
 

55. The carbon seal ring of a refrigeration compressor crankshaft mechanical seal is held in position against the stationary ring face by using what device?

 
 
 
 

56. If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true?

 
 
 
 

57. In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive component?

 
 
 
 

58. When one belt of a multiple V-belt drive requires replacing, what will be required?

 
 
 
 

59. Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition?

 
 
 
 

60. When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening?

 
 
 
 

61. A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning the discharge service valve all the way in, and then turning the compressor over by hand. If the discharge valves are leaking, the compound gage will show pressures which react in which way?

 
 
 
 

62. Unusual noise coming from a refrigeration compressor can be caused by which of the following conditions?

 
 
 
 

63. Which of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor?

 
 
 
 

64. Leaking suction valves in a refrigeration compressor are indicated by which of the following?

 
 
 
 

65. If a liquid drying agent is used in a refrigeration system already equipped with a solid drying agent, the liquid drying agent will cause what type of reaction?

 
 
 
 

66. Why are dehydrators usually located in the liquid line of refrigeration systems?

 
 
 
 

67. In a refrigeration system, silica gel is found in what component?

 
 
 
 

68. Standard filter/driers used in many commercial type refrigeration units may contain what type of substance?

 
 
 
 

69. Which of the devices listed will indicate whether or not a refrigeration system's dehydrator continues to be capable of removing moisture from the circulating refrigerant?

 
 
 
 

70. Moisture is removed from a refrigeration system by what action?

 
 
 
 

71. For most multi-box refrigeration systems, the refrigerant sight glass would be located where in the system?

 
 
 
 

72. A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently charged. Where is it generally located in the system?

 
 
 
 

73. The primary purpose of the liquid line strainer used in a refrigeration system is to prevent dirt and scale from entering what system component(s)?

 
 
 
 

74. Capacity control of a centrifugal refrigeration compressor can be accomplished by what means?

 
 
 
 

75. During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value?

 
 
 
 

76. On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase?

 
 
 
 

77. To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes?

 
 
 
 

78. A box solenoid valve used in a multi-box refrigeration system is operated by electro-magnetic action by what control device?

 
 
 
 

79. In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device?

 
 
 
 

80. A liquid line solenoid valve controls refrigerant flow to the evaporator by what means?

 
 
 
 

81. How does a refrigeration solenoid valve differ from a modulating valve?

 
 
 
 

82. In a refrigeration system featuring low-side pump down prior to the automatic shut down of the compressor, the temperature of the refrigerated space is controlled by the action of a thermostat wired to what device?

 
 
 
 

83. The thermostat controlling the operation of the solenoid valve to a refrigerated box evaporator senses what temperature?

 
 
 
 

84. What is the purpose of the low pressure cut-out switch as used as a primary controller for a refrigeration system or unit?

 
 
 
 

85. An arrow stamped on the valve body of a water regulating valve indicates which of the following?

 
 
 
 

86. The receiver used in a refrigeration system performs what essential function?

 
 
 
 

87. Refrigeration system isolation valves are specially designed with a back-seat, as well as a front-seat. For what purpose are these valves designed in this way?

 
 
 
 

88. In a refrigeration plant, what is one vital purpose of the receiver?

 
 
 
 

89. In addition to pressure, most compound and standard pressure gauges used for refrigeration service are also provided with a scale indicating what parameter?

 
 
 
 

90. Hard drawn copper tubing is commonly used in larger refrigeration systems. What statement concerning its use is true?

 
 
 
 

91. In a large refrigeration system having more than one evaporator, a king solenoid valve should be installed in what location?

 
 
 
 

92. During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to prevent excessive gas pressure at the compressor suction for the purpose of prevention of overloading of the compressor driver?

 
 
 
 

93. The rupture disc on a low pressure centrifugal refrigeration unit is used as an over pressure protection device and is set to relieve at 15 psig and is most likely to lift when the compressor is idle? Where is the rupture disc located?

 
 
 
 

94. When the relief valve opens on a refrigeration compressor discharge line, it discharges high pressure refrigerant vapor to what location

 
 
 
 

95. In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, what will be the result for protective purposes?

 
 
 
 

96. In a refrigeration system, what component is installed directly downstream of the thermal expansion valve?

 
 
 
 

97. Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in chill boxes. Which of the following will minimize this dehydration?

 
 
 
 

98. In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils?

 
 
 
 

99. Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located where?

 
 
 
 

100. Seawater or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose?

 
 
 
 


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