MCQ in Refrigeration Engineering Part 2 | ME Board Exam

(Last Updated On: December 26, 2020)

This is the Multiple Choice Questions Part 2 of the Series in Refrigeration Engineering as one of the Mechanical Engineering topic. In Preparation for the ME Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Mechanical Engineering field, Mechanical Engineering Books, Journals and other ME References. I assume you are looking for a reviewer that will help you achieve your goal to become a License Mechanical Engineer very soon. Yes, you are in the right place to make your dream come true. Make sure to familiarize each and every questions to increase the chance of passing the Mechanical Board Examination.

MCQ Topic Outline included in ME Board Exam Syllabi

• MCQ in Principles of Different Refrigeration Systems
• MCQ in Determination of Cooling Loads
• MCQ in Basic Design of Ice Plants, Cold Storage and Skating Rinks
• MCQ in Instrumentation and Controls

Continue Practice Exam Test Questions Part 2 of the Series

⇐ MCQ in Refrigeration Engineering Part 1 | ME Board Exam

Choose the letter of the best answer in each questions.

51. Air circulation in the icebox is accomplished by the use of which of the following?

A. hollow sidewalls

B. diffuser fans

C. louver doors

D. air vents to deck

52. The cooling-water side of the condenser should be opened for inspection every

A. six months

B. two years

C. year

D. three months

53. Some causes of a noisy compressor are

A. worn bearing, pins, etc.

B. slugging due to flooding back of refrigerant

C. too much oil on crankcase

D. any of these

54. If the thermal expansion valve becomes inoperative, the iceboxes will have to be controlled the ______

A. king valve

B. manual expansion valve

C. manual solenoid valve

D. solenoid valve

55. Sweating of the crankcase is caused by which of the following ?

A. too much oil in the system

B. insufficient superheat

C. too much superheat

D. expansion valve hung up

56. Which of the following is the usual cause of slugging?

A. too much refrigerant in the system

B. too much oil in the system

C. expansion valve not operating properly

D. too much cooling water to condenser

57. What operates low-pressure cutout switch?

A. bellows

B. spring tension

C. a magnet

D. water pressure

58. Which of the following must be checked up if an automatic Freon system will not start up?

A. high-pressure cutout

B. reset mechanism

C. low-pressure cutout

D. all of these

59. Which of the following is the probable cause of hot suction line?

A. insufficient lubrication

B. too much refrigerant

C. insufficient refrigerant

D. expansion valve closed too much

60. What do you call the device that is used as a low-pressure control and high-pressure cutout on a compressor

A. pressure controller

B. controller switch

C. cutout

D. cutout switch

61. If the solenoid valve closed by accident, the compressor would be stopped by which of the following?

A. automatic trip

B. low-pressure cutout switch

C. low-water cutout switch

D. high-pressure cutout switch

62. The purpose of the low-pressure cutout switch is to:

A. cutout the compressor at a set pressure

B. maintain a preset suction pressure to the compressor

C. maintain liquid refrigerant at the suction of the compressor

D. cut compressor in and out at a preset pressure

63. If the cooling water to the condenser suddenly fails?

A. an alarm will ring to notify the engineer

B. the compressor will shut down

C. the expansion valve will close

D. the solenoid valve will close

64. The most likely cause of high superheat would be

A. too much refrigerant

B. expansion valve open too wide

C. expansion valve closed too much

D. back-pressure valve set too high

65. What do you call the liquid researching the compressor through the suction

A. superheating

B. overflowing

C. flooding back

D. recycling

66. The suction pressure switch is operated by which of the following?

A. electronic current

B. pressure on a bellows

C. a relay cutout

D. thermocouple

67. If the compressor short-cycles on the high-pressure cutout, which of the following would you check?

A. a check for too much refrigerant in the system

B. if plenty of cooling water is running through but it is not picking up heat, the condenser tubes need cleaning

C. be sure system is getting cooling water

D. all of these

68. A Freon unit will tend to short-cycle when operating under :

A. normal conditions

B. heavy loads

C. light loads

D. all of these

69. Air is remove from the system by

A. opening the purge valve

B. increasing the amount of cooling water

C. running the refrigerant through an aerator

D. running the refrigerant through a deaerator

70. Short-cycling means that the machine

A. runs to slow

B. stops and starts frequently

C. runs too fast

D. grounds out frequently

71. The suction pressure in a Freon system should be

A. the pressure which corresponds with a temperature about 20o F above the temperature of the icebox.

B. the pressure corresponds with a temperature about 200 F below the temperature of the icebox

C. the pressure which corresponds with a temperature equal to the temperature of the icebox

D. none of these

72. If any of the electrically controlled devices in a Freon system malfunction, which of the following valve will also automatically shut off?

A. king valve

B. Condenser cooling-water inlet valve

C. Expansion valve

D. Solenoid valve

73. A leaky discharge valve can usually be detected by

A. a drop in icebox temperature

B. a discharge pressure lower than normal

C. a fluctuating high-pressure gauge

D. any of these

74. The dehydrating agent in a Freon system is usually

A. sodium chloride

B. calcium chloride

C. activated alumina

D. slaked lime

75. If the compressor short-cycles on the low-pressure cutout, the trouble might be :

A. too much frost on the evaporator coils

B. dirty traps and strainers

C. lack of refrigerant

D. any of these

76. If an electrically operated compressor failed to start, the cause might be:

A. a blown fuse

B. burned out holding coils in solenoid valve

C. an open switch

D. any of these

77. The high-pressure side of the system is sometimes referred to as the

A. hot side

B. suction side

C. cold side

D. cooling side

78. If the compressor were to run continuously without lowering the temperature, the trouble would probably be:

A. leaky discharge valves

B. insufficient refrigerant in the system

C. leaks in the system

D. any of these

79. Which of the following would cause a high head pressure?

A. suction valve not open enough

B. too much cooling water

C. insufficient cooling water

D. icebox door left open

80. If frost forms on the cylinders, the cause would be

A. charging valve left open

B. expansion valve not open wide enough

C. expansion valve open too wide

D. dehydrator not working properly

81. Which of the following would cause low head pressure?

A. insufficient cooling water

B. too much cooling water

C. insufficient refrigerant gas

D. B and C

82. Too high suction pressure could be cause by

A. leaky suction valves

B. expansion valve bulb not working properly

C. expansion value open too wide

D. any of these

83. Which of the following would cause high head pressure?

A. air in the condenser

B. insufficient cooling water

C. dirty condenser

D. any of these

84. An excessively high head pressure could be caused by

A. insufficient cooling water to the condenser

B. insufficient cooling water to the evaporator coils

C. solenoid valve shutoff

D. too much cooling water to the condenser

85. Which of the following would cause a high suction pressure?

A. expansion valve open too wide

B. dirty dehydrator

C. king valve not open wide enough

D. expansion valve not open wide enough

86. If a compressor runs continuously, the cause might be a

A. clogged scale trap

B. defective thermal bulb

C. stuck high-pressure switch

D. stuck low-pressure switch

87. Low suction pressure is caused by

A. expansion valve causing flooding back

B. solenoid valve not functioning properly

C. leaky compressor suction valves

D. air in the system

88. How is a Freon system purged?

A. with a reefer pump

B. the same as an ammonia system

C. back to the extra supply tank

D. the same as a CO₂ system

89. If the compressor discharge temperature is higher than the receiver temperature :

A. add more refrigerant to the system

B. decrease the amount of cooling water to the condenser

C. increase the amount of cooling water to the condenser

D. remove some of the refrigerant from the system

90. How is a CO₂ system purged?

A. when is a CO2 comes out of the purge valve, frost will from on a piece of metal held near the outlet

B. through the king valve

C. pumped out with a suction pump

D. the CO₂ will come of the purge valve in liquid form

91. If the head pressure is too high:

A. the relief valve should open and let excess refrigerant pass to receiver

B. close in on the suction valve

C. the relief should open before the high-pressure cutout

D. the high-pressure cutout switch should operate before the relief value opens

92. The system should be purged

A. while starting up

B. after the system has been shut down for a few hours

C. while system is operating

D. once a week

93. If the compressor had been running satisfactorily for a long period of time but suddenly the compartment temperature started to rise, the trouble must be

A. a refrigerant leak has developed

B. the expansion valve may contain frozen water

C. the solenoid valve has jammed shut

D. any of these

94. If the compressor had been running satisfactorily for a long period of time but the oil level was rising slowly, one should :

A. check the dehydrator cartridge

B. check to see if there is too much refrigerant in the system

C. shut down the compressor and check the oil level with the machine stopped

D. drain out sufficient oil to bring it down to the proper running level

95. The purpose of the trap is :

A. to add oil to the compressor

B. to remove oil from the refrigerating gas

C. to remove oil from the charging tank

D. none of these

96. Too much oil in the compressor would :

A. absorb too much refrigerant from the system

B. deposit oil on the condenser tubes

C. damage the expansion valve

D. caused leakage through the shaft seals

97. The oil level in the compressor should be checked

A. just before starting the compressor

B. after a long period of operation

C. after an extended lay-up period

D. while the compressor is in operation

98. The agent used in an indirect reefer system is

A. calcium chloride

B. potassium chloride

C. sodium chloride

D. A or C

99. Air can be prevented from getting into system by

A. running the refrigerant through an aerator

B. keeping the dehydrator clean at all times

C. keeping all glands and stuffing boxes on the high-pressure side tight

D. keeping all glands and stuffing boxes on the

100. Which of the following would not cause high suction pressure?

A. suction valve not adjusted properly

B. expansion valve stuck open

C. leaky suction valve

D. insufficient refrigeration