Air Conditioning Assessment Flashcards by Cooper Hines

Heat which causes a change in temperature of a substance is called;
A. Latent Heat
B. Sensible Heat
C. Superheat
D. Regular Heat

B. Sensible Heat

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Heat Which causes a change in state of a material without a change in temperature is called;
A. Latent Heat
B. Sensible Heat
C. Superheat
D. Regular Heat

A. Latent Heat

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Heat Which is added to a vapor after the change of state occurs is called;
A. Latent Heat
B. Subcooling
C. Superheat
D. Regular Heat

C. Superheat

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Heat can travel by;
A. Conduction
B. Convection
C. Radiation
D. Conduction, Convection, Radiation

D. Conduction, Convection, Radiation

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The movement of heat by way of fluid (or air) is called;
A. Conduction
B. Convection
C. Radiation
D. Conduction, Convection, Radiation

B. Convection

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The movement of heat by direct contact is called;
A. Conduction
B. Convection
C. Radiation
D. Conduction, Convection, Radiation

A. Conduction

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The standard unit for measuring the quantity of heat in a substance is;
A. Degrees Fahrenheit
B. Degrees Celcius
C. Degrees Rankin
D. British Thermal Unit (BTU)

D. British Thermal Unit (BTU)

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A refrigerant gives up heat when;
A. It condenses
B. It evaporates
C. It is compressed
D. It vaporizes

A. It condenses

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It is desirable for refrigerant in the suction line to be slightly superheated in order to;
A. Ensure liquid refrigerant does not enter the compressor.
B. Prevent vapor refrigerant from entering the compressor.
C. Keep the compressor warm.
D. Prevent vapor refrigerant from entering the condenser.

A. Ensure liquid refrigerant does not enter the compressor.

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The state of the refrigerant in the suction line should be;
A. High Pressure/High Temperature Liquid
B. High Pressure/ Low Temperature Vapor
C. Low Pressure/ Low Temperature Liquid
D. Low Pressure/ Low Temperature Vapor

D. Low Pressure/ Low Temperature Vapor

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The state of the refrigerant entering the condenser is;
A. High Pressure/ Highly Superheated Liquid
B. High Pressure/ Highly Superheated Vapor
C. High Pressure/ High Temperature Liquid
D. Low Pressure/ Low Temperature Vapor

B. High Pressure/ Highly Superheated Vapor

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The evaporator;
A. Transfers heat from the refrigerated space to the refrigerant.
B. Transfers heat from the refrigerant to the refrigerated space.
C. Transfers heat from the refrigerant to the ambient air.
D. Transfers heat from the ambient air to the refrigerated space.

A. Transfers heat from the refrigerated space to the refrigerant.

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Which of the following is NOT a thermodynamic property of refrigerants?
A. Critical Point
B. Saturation Point
C. Enthalpy
D. Flammability

D. Flammability

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The sequential order of the steps in the vapor-compression process are;
A. Expansion, condensation, compression, vaporization.
B. Vaporization, expansion, condensation, compression.
C. Compression, condensation, expansion, vaporization.
D. Expansion, Compression, Vaporization, Condensation.

C. Compression, condensation, expansion, vaporization.

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If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored over night at 70 F, the pressure in the cylinder should be approximately;
A. 201 PSI
B. 168 PSI
C. 143 PSI
D. 118 PSI

A. 201 PSI

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Fan airflow pressures are usually measured in;
A. Inches of mercury vacuum or microns.
B. Microns or PSIG
C. PSIG or Inches of mercury vacuum.
D. Inches of water column (WC)

D. Inches of water column (WC)

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Zero PSIA (Pounds per Square Inch Absolute) is;
A. The same as atmospheric pressure.
B. Approximately 14.7 PSI at sea level.
C. A pressure which cannot be further reduced.
D. Equal to 500 microns.

B. Approximately 14.7 PSI at sea level.

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Zero PSIG (Pounds per Square Inch Gauge) is;
A. 25,400 microns
B. Approximately 29.9 PSIA at sea level.
C. A pressure which cannot be further reduced.
D. The same as atmospheric pressure.

D. The same as atmospheric pressure.

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The temperature at which moisture will start to condense from the air is called;
A. Dry Bulb Temperature
B. Wet Bulb Depression
C. Dew Point Temperature
D. Condensate Point

C. Dew Point Temperature

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A compound pressure gauge measures;
A. Pressure and vacuum
B. Pressure and temperature
C. Pressure and humidity
D. Wet and Dry Bulb Temperatures

A. Pressure and vacuum

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A mechanical shaft seal is necessary on a;
A. Semi-hermetic compressor
B. Hermetic reciprocating compressor
C. Hermetic rotary compressor
D. Open drive compressor

D. Open drive compressor

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Liquid Slugging is;
A. A pounding noise caused by liquid refrigerant in the suction line at the point of a restriction.
B. Noise caused by excessive liquid refrigerant in the condenser.
C. Liquid refrigerant in the compressor clearance space.
D. Excessive liquid refrigerant in the receiver.

C. Liquid refrigerant in the compressor clearance space.

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The clearance space in a reciprocating compressor;
A. Has no effect on compressor capacity.
B. Has an effect on compressor capacity.
C. Varies depending on compressor speed.
D. Is the same on all compressors.

D. Is the same on all compressors.

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Which of the following types of air conditioning compressors is most energy efficient?
A. Reciprocating
B. Centrifugal
C. Rotary Vane
D. Scroll

B. Centrifugal

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25. The main function of the condenser is to; A. Store liquid refrigerant. B. Remove heat from the refrigerant. C. Remove moisture from the refrigerant. D. Add heat to the refrigerant.

B. Remove heat from the refrigerant.

26. Refrigerant R-134A vapor enters the condenser at 124 PSI, 100 F. It leaves the condenser at 80 F. It's pressure will be approximately; A. 76 PSIG B. 87 PSIG C. 106 PSIG D. 124 PSIG

D. 124 PSIG

27. There are three basic types of condensers, the air cooled, the water cooled and the _________ cooled. A. Evaporative B. Expansion C. Gas D. Double Pipe

A. Evaporative

28. 10 lbs. of refrigerant passing through a water cooled condenser will lose 20 BTU's of heat per lb. If 10 lbs. of water passes through the condenser with an entering temperature of 80 F, then the temperature of the water leaving the condenser is; A. 80 F B. 95 F C. 100 F D. 110 F

B. 95 F

29. The heat removed from the refrigerant by the condenser is; A. Sensible Heat only. B. Latent Heat only. C. Both sensible and latent heat. D. Neither sensible and latent heat.

C. Both sensible and latent heat.

30. Which of the following CANNOT be used as a low ambient temperature control? A. Fan cycling B. Air Shutters or Dampers C. Condenser Flooding D. Crankcase Regulating Valve

D. Crankcase Regulating Valve

31. When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature should be no more than __________ higher than the entering air temperature. A. Approximately 30 F B. Approximately 80 F C. Approximately 100 F D. Approximately 5 F

A. Approximately 30 F

32. When testing the efficiency of a water cooled condenser, the refrigerant condensing temperature should be no more than _________ higher than the leaving water temperature. A. Approximately 10 F B. Approximately 30 F C. Approximately 50 F D. Approximately 5 F

A. Approximately 10 F

33. The first function a condenser must perform is to __________ the refrigerant before condensing can occur. A. Superheat B. De-Superheat C. Compress D. Subcool

B. De-Superheat

34. A thermostatic expansion valve is designed to maintain; A. Constant evaporator temperature. B. Constant refrigerant flow. C. Constant evaporator Superheat. D. Constant evaporator pressure.

C. Constant evaporator Superheat.

35. The automatic expansion valve is designed to maintain; A. Constant evaporator temperature. B. Constant refrigerant flow. C. Constant evaporator Superheat. D. Constant evaporator pressure.

D. Constant evaporator pressure.

36. The thermostatic expansion valve has three operating pressures; A. Evaporator pressure, spring pressure and suction bulb pressure B. Evaporator pressure, spring pressure and condensing bulb pressure C. Evaporator pressure, spring pressure and liquid bulb pressure D. Evaporator pressure, spring pressure and sensor bulb pressure

D. Evaporator pressure, spring pressure and sensor bulb pressure

37. When mounting a thermostatic expansion valve sensor bulb, which of the following is NOT true? A. The contact surfaces must be clean. B. It must be tightly clamped to the suction line. C. It must be insulated from ambient temperature. D. It must be installed lower than the valve body.

D. It must be installed lower than the valve body.

38. In an air conditioning system that uses a thermostatic expansion valve, the temperature of the evaporator outlet will usually be; A. Cooler than the evaporator inlet. B. Warmer than the evaporator inlet. C. The same as the evaporator inlet. D. Unchanged by superheat.

B. Warmer than the evaporator inlet.

39. An automatic expansion valve is best suited; A. When the system load remains fairly constant. B. When the system load varies greatly. C. When the compressor must start often. D. When multiple evaporators are used.

A. When the system load remains fairly constant.

40. Which of the following is NOT true of a capillary tube metering device? A. They have no moving parts. B. They allow pressures to equalize after the compressor shuts down. C. They maintain a constant evaporator temperature. D. They are sized to match system capacity.

C. They maintain a constant evaporator temperature.

41. A decrease in Superheat causes the thermostatic expansion valve to begin to; A. Open B. Close C. Flood the evaporator D. Starve the evaporator

B. Close

42. A rise in evaporator pressure causes the automatic expansion valve to begin to; A. Open B. Close C. Flood the evaporator D. Starve the evaporator

B. Close

43. A thermal-electric (solid state) expansion valve is controlled by; A. Suction Pressure B. NTC Thermistor C. Thermal Bulb D. External Equalizing Port

B. NTC Thermistor

44. In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator as; A. Liquid only B. Vapor only C. A mixture of liquid with some "flash-gas." D. Superheated vapor only

C. A mixture of liquid with some "flash-gas."

45.Which of the following is the most important consideration in the selection of an evaporator coil? Match the coli to the; A. Sensible capacity of the condensing unit. B. Latent capacity of the condensing unit. C. Latent capacity and outdoor design temperature. D. Condensing unit and the latent/sensible loads.

D. Condensing unit and the latent/sensible loads.

46. In the evaporator; A. Latent heat is transferred from the refrigerated space to the refrigerant. B. Latent heat is transferred from the refrigerant to the refrigerated space. C. The refrigerant changes from a vapor to a liquid. D. The refrigeration system reaches its highest pressure.

A. Latent heat is transferred from the refrigerated space to the refrigerant.

47. A liquid line filter-drier should be placed between the; A. Evaporator and Compressor B. Compressor and Condenser C. Condenser and the Metering Device D. Metering Device and the Evaporator

C. Condenser and the Metering Device

48. A temperature differential across a filter-drier indicates; A. Normal operation B. A refrigerant overcharge C. A restricted filter-drier D. A refrigerant undercharge

C. A restricted filter-drier

49. A liquid receiver is used to; A. Prevent liquid refrigerant from reaching the compressor. B. Separate oil from the liquid refrigerant. C. Store liquid refrigerant. D. Receive and store vapor refrigerant.

C. Store liquid refrigerant.

50. An accumulator is used to; A. Prevent liquid refrigerant from reaching the compressor. B. Separate oil from the liquid refrigerant. C. Store liquid refrigerant. D. Receive and store vapor refrigerant.

A. Prevent liquid refrigerant from reaching the compressor.

51. A sight glass would normally be located; A. In the liquid line, before the metering device. B. In the liquid line, after the metering device. C. In the suction line, before the compressor. D. In the suction line, after the compressor.

A. In the liquid line, before the metering device.

52. Bubbles in a sight glass could be an indication of; A. An overcharge of refrigerant B. Low compressor capacity C. TEV with an excessive Superheat setting D. A refrigerant blend with a high temperature glide

D. A refrigerant blend with a high temperature glide

53. Which of the following symptoms would be indicative of an oil logged condenser? A. High liquid line pressure and low discharge line pressure. B. Low Superheat C. High discharge line pressure and low liquid line pressure D. High subcooling

C. High discharge line pressure and low liquid line pressure

54. Which of the following is TRUE of a solenoid valve in a pump down system? A. It is located after the metering device. B. It is located before the metering device. C. It is located after the evaporator. D. It is used instead of a metering device.

B. It is located before the metering device.

55. The purpose of an evaporator pressure regulating valve (EPR) is to; A. Prevent low Superheat B. Prevent high Superheat C. Prevent migration of refrigerant to the compressor during the off cycle. D. Prevent evaporator pressure from falling below a set limit.

D. Prevent evaporator pressure from falling below a set limit.

56. A liquid-to-suction heat exchanger is often used to; A. Decrease vapor Superheat B. Increase liquid Subcooling C. Decrease head pressure D. Increase flash gas in the suction line

B. Increase liquid Subcooling

57. The oil pressure safety switch is operated by; A. The sum of suction pressure and oil pressure. B. The sum of oil pressure and crankcase pressure. C. The difference between crankcase pressure and oil pressure. D. The difference between head pressure and oil pressure.

C. The difference between crankcase pressure and oil pressure.

58. A low pressure cut-off switch is used to; A. Establish a minimum operating pressure in the evaporator. B. Prevent condensing pressure from reaching dangerously high levels. C. Sense oil pressure in the lower portion of the compressor. D. Prevent low oil pressure in the crankcase.

C. Sense oil pressure in the lower portion of the compressor.

59. A partially iced over evaporator can be caused by; A. An overcharge B. Excessive air flow C. An undercharge D. High indoor humidity

C. An undercharge

60. _________ can be used for leak detection with all high pressure refrigerants. A. Soap Bubbles B. Halide torch C. Open flame D. Electronic Halogen Detector

A. Soap Bubbles

61. The flow rate of a TXV used in R-410A systems as compared to R-22 systems is; A. Equal B. Approximately 40% to 70% higher C. Approximately 15% greater D. Approximately 15% less

D. Approximately 15% less

62. When using an electronic leak detector, the sensor probe; A. Must be moved around suspected areas as fast as possible. B. Must be exposed to a large amount of refrigerant for calibration. C. Should be moved at approximately 1 inch per second. D. Is not affected by dirt or oil.

C. Should be moved at approximately 1 inch per second.

63. Moisture in a refrigeration system will cause; A. Low head pressure B. High suction pressure C. Evaporator icing D. Compressor failure

D. Compressor failure

64. In order to remove as much moisture as possible from a system; A. Flush and purge the system with liquid refrigerant. B. Apply heat to the accumulator of the system. C. Use the largest vacuum pump available with long hoses to allow condensing. D. Triple evacuate the system to 500 microns with a deep vacuum pump.

D. Triple evacuate the system to 500 microns with a deep vacuum pump.

65. What type of gauge is used to measure microns? A. A high pressure gauge B. A compound gauge C. An electronic vacuum gauge D. A mercury manometer

C. An electronic vacuum gauge

66. Water will vaporize at what temperature in a 28" Hg vacuum? A. 100 F B. 10 F C. 212 F D. 250 F

A. 100 F

67. Before a vapor/compression system is opened for service; A. The refrigerant must be released to the atmosphere. B. The refrigerant must be recovered using approved equipment. C. The refrigerant may be vented only if it is an HCFC. D. The refrigerant may be vented only if it is an HFC.

B. The refrigerant must be recovered using approved equipment.

68. Back seating a two way service valve results in; A. Open service port with normal system flow. B. Closed service port with normal system flow. C. Open service port with the system flow blocked. D. Closed service port with the system flow blocked.

B. Closed service port with normal system flow.

69. The R-410A compound gauge reads 124 PSIG and the suction line temperature at the condensing unit is 54 F. What is the operating system Superheat? A. 96 F B. 30 F C. 12 F D. 6 F

C. 12 F

70. When topping off an operating system containing a blended refrigerant; A. Introduce the refrigerant as a liquid into the low side using a throttling valve. B. Introduce the refrigerant as a vapor into the low side using a throttling valve. C. Introduce the refrigerant as a liquid through the high side. D. Weigh in the refrigerant as a vapor into the low side.

A. Introduce the refrigerant as a liquid into the low side using a throttling valve.

71. A partially clogged capillary tube can cause; A. High head pressure B. A starved condenser C. A starved evaporator D. A flooded evaporator

C. A starved evaporator

72. The R-134A high pressure gauge reads 143 PSI and the liquid line temperature at the condensing unit is 95 F. What is the operating system subcooling? A. 238 F B. 48 F C. 35 F D. 13 F

D. 13 F

73. An overcharge of refrigerant will cause; A. Increased head pressure B. Decreased head pressure C. Bubbles in the sight glass D. Frost on the condenser

A. Increased head pressure

74. A customer complains that their air conditioning system is running constantly, but not cooling enough. The suction line is very cold and the compressor is sweating. The most likely cause is; A. A low refrigerant charge. B. A restriction of the return air or a dirty evaporator. C. High humidity conditions with a blocked condensate tube. D. The thermostat is set too low.

B. A restriction of the return air or a dirty evaporator.

75. What is the minimum vertical drop from the outlet of the condensate drain pan to the inlet of the P trap? A. 9 inches B. 7 inches C. 5 inches D. 3 inches

D. 3 inches

76. A customer reports that their residential split system had a compressor replaced last week by another service company. Now the unit is not cooling properly. When you arrive and inspect the unit, you find that the evaporator seems to be starved for refrigerant. On examining the condensing unit, you find that the liquid line is sweating where it leaves the drier. This is most likely the result of; A. Debris from the burned out compressor that have clogged the drier. B. Air in the system. C. A defective replacement compressor. D. Refrigerant overcharge.

A. Debris from the burned out compressor that have clogged the drier.

77. What is the generally accepted range for evaporator air flow in CFMs per ton of residential air conditioning? A. 150 to 250 B. 250 to 350 C. 350 to 450 D. 450 to 550

C. 350 to 450

78. The temperature rise method of determining air volume can be used on; A. Gas fired furnace B. Oil fired furnace C. Electric resistive heat air handler D. Condensing oil fired boiler

C. Electric resistive heat air handler

79. What is the recommended residential indoor relative humidity for summer? A. 70% B. 60% C. 50% D. 40%

D. 40%

80. An inefficient compressor is usually indicated by _______ head pressure and ________ suction pressure. A. Lower than normal/Higher than normal B. Higher than normal/Lower than normal C. Lower than normal/Lower than normal D. Higher than normal/Higher than normal

A. Lower than normal/Higher than normal

81. Which of the following is NOT a symptom of a hermetic system that is low on refrigerant? A. Low head pressure B. Low suction pressure C. High head pressure D. Frost on the evaporator

C. High head pressure

82. Frost on the suction line indicates; A. That its temperature is below the dew point and below 32 F. B. A flooded evaporator C. Low Superheat setting D. A refrigerant overcharge

A. That its temperature is below the dew point and below 32 F.

83. An increase in head pressure causes ____________ refrigerant to flow through a capillary tube. A. More B. Less C. No D. The same amount of

A. More

84. When an automatic expansion valve is used as a metering device, a low refrigerant charge will cause; A. High suction pressure B. High head pressure C. High Superheat D. Low Superheat

C. High Superheat

85. When a TEV or a capillary tube is used as a metering device, a low refrigerant charge will cause; A. High suction pressure B. High head pressure C. Low Superheat D. Low head pressure

D. Low head pressure

86. What is the maximum operating pressure setting for an acetylene torch? A. 10 PSIG B. 15 PSIG C. 20 PSIG D. 25 PSIG

B. 15 PSIG

87. When connecting copper to steel, the recommended brazing filler alloy is a; A. 45% silver alloy B. Copper/phosphorus alloy C. 50/50 solder alloy D. 5% silver alloy

A. 45% silver alloy

88. Solid contaminants such as sludge and carbon from a severe hermetic compressor motor burn out are best removed; A. By blowing the system out with refrigerant and then installing filter-driers in both the liquid and suction lines. B. By flushing the system and then installing filter-driers in both the liquid and suction lines. C. By blowing the system out with compressed air and then installing filter-driers in both the liquid and suction lines. D. By installing filter-driers in both the liquid and suction lines.

B. By flushing the system and then installing filter-driers in both the liquid and suction lines.

89. If the cut off plate is removed from a blower assembly, how would this effect blower performance? A. It would increase air flow. B. It would reduce air flow. C. Blower motor performance would increase. D. Blower motor would operate correctly.

B. It would reduce air flow.

90. At a residential service call, "no cooling" complain, the service technician finds the unit to be completely out of refrigerant. The technician decides to use a trace amount of refrigerant and _______ in order to pressurize the system. A. Compressed air B. Oxygen C. An inert gas D. Carbon monoxide

C. An inert gas

91. A technician has found an air conditioning system with a leak in the liquid line. After the line is repaired, the system is evacuated and properly recharged. When the system is started, the compressor is noisy and running hot. The most probable cause of the noise is; A. Refrigerant overcharge B. Air in the system C. Low oil in the system D. Refrigerant undercharge

C. Low oil in the system

92. An air conditioning system that is oversized can cause; A. Increased compressor life B. Better comfort range C. Improved dehumidification of the conditioned space D. Inefficient dehumidification of the conditioned space

D. Inefficient dehumidification of the conditioned space

93. While troubleshooting a residential split system, the service technician finds low operating pressures and low system amperage draw. This could be an indication of; A. Low airflow across the evaporator B. High ambient temperature C. A dirty condenser D. Air in the system

A. Low airflow across the evaporator

94. Air or other non-condensable gases in a capillary tube air conditioning system will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

B. High suction pressure and high discharge pressure

95. A refrigerant overcharge in a capillary tube air conditioning system will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

B. High suction pressure and high discharge pressure

96. A compressor that has a broken reed valve will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

A. High suction pressure and low discharge pressure

97. A low refrigerant charge in an air conditioning system will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

C. Low suction pressure and low discharge pressure

98. A TEV sensing bulb which becomes detached from the suction line will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

B. High suction pressure and high discharge pressure

99. A faulty condenser fan motor on an air conditioning system will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

B. High suction pressure and high discharge pressure

100. A dirty evaporator in an air conditioning system will cause these symptoms; A. High suction pressure and low discharge pressure B. High suction pressure and high discharge pressure C. Low suction pressure and low discharge pressure D. Low suction pressure and high discharge pressure

C. Low suction pressure and low discharge pressure

Air Conditioning Assessment Flashcards

(100 cards)