Heat Pumps

Heat Pumps

Multiple ChoiceIdentify the letter of the choice that best completes the statement or answers the question.

1. A micron gauge is used to measure ____.a. atmospheric pressures at high altitudesb. atmospheric pressures at sea levelc. absolute pressures below 1 mm Hgd. high pressure in a refrigeration system

ANSWER: CPOINTS: 0 / 1

2. Moisture in a liquid state must be ____ before it can be removed with a vacuum pump.a. vaporizedb. condensedc. cooledd. solidified

ANSWER: APOINTS: 0 / 1

3. Comfort can be described as the gentle balance between ____.a. air cleanliness, air movement, temperature, and humidityb. air velocity, air cleanliness, humidity, and air movementc. air speed, air velocity, temperature, and humidityd. acceleration, air cleanliness, filtration, and humidity


4. If 30 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 26 lb. 4 oz. before any is added, what will the supply cylinder weigh after the system has been charged?a. 22 lb. 8 oz.b. 24 lb. 6 oz.c. 24 lb. 8 oz.d. 22 lb. 4 oz.

ANSWER: BPOINTS: 0 / 1

5. The factory charge in a split system, using R-22, shows 6 lb. 8 oz. in the

outdoor condensing unit and 2 oz. in the evaporator. The 3/8" liquid line contains 0.48 oz. per foot and the 7/8" suction line contains 0.10 oz. per foot. The refrigerant lines are 30' long. What is the correct refrigerant charge for this system?a. 6 lb. 10 oz.b. 6 lb. 15 oz.c. 7 lb. 7 oz.d. 7 lb. 11 oz.

ANSWER: DPOINTS: 0 / 1

6. A graduated cylinder charging device is a device that ____.a. measures refrigerant by volume for precise refrigerant chargingb. has a compensation dial for adjusting for the temperature of the

refrigerantc. often has a heater to keep the refrigerant temperature from dropping

when refrigerant is released into the systemd. all of the above


7. The generalized comfort chart can be used as a basis to ____.a. determine combinations of temperature and humidity to produce

comfort in summer and winterb. study air and its propertiesc. determine the amount of fresh air make up necessary for comfortd. none of the above


8. The density of air is the ____.a. amount of moisture in the airb. amount of movement in the air per cubic footc. weight of the air per cubic footd. combination of the temperature and pressure of the air


9. Of the heat produced in the human body, which is by perspiration?a. conductionb. convectionc. radiation

d. evaporation


10. Refrigerant in vapor form is normally put into the system through the ____.a. liquid lineb. suction linec. hot gas lined. liquid return line


11. Termination of the defrost cycle occurs when the liquid off the outside coil reaches ____.a. 35°Fb. 45°Fc. 50°Fd. 65°F


12. A compound gauge ____.a. indicates pressures above 14.696 psiab. indicates pressures in inches Hg below atmospheric pressurec. is one of two gauges on a typical gauge manifoldd. all of the above


13. The wet-bulb temperature ____.a. is the same as the wet-bulb depressionb. is the saturation pressurec. takes into account the moisture content of the aird. is always higher than the dry-bulb temperature


14. If a technician connects gauges on the line set of the outdoor unit of a heat pump operating in the heating mode, ____.a. the high pressure gauge will read the high side pressure and the low

pressure gauge will most likely be in the RETARD range

b. the high pressure gauge will read the high side pressure and the low pressure gauge will read the suction pressure

c. both gauges will read the suction pressured. the high pressure gauge will read the suction pressure and the low

pressure will read discharge pressure


15. A pressure-temperature defrost control is activated by the ____.a. difference of the pressure in the fan compartment and the

temperature of the coilb. difference in pressure between the outdoor pressure and the fan

discharge pressurec. difference in the pressure of the air through the outdoor coild. difference in pressure of the refrigerant in the condenser and the

pressure in the coil


16. What is the dew-point temperature if the wet-bulb temperature is 65°F and the dry-bulb temperature is 100°F?a. 40°Fb. 50°Fc. 60°Fd. 70°F


17. Infiltration is the term used when referring to the air entering a structure ____.a. through an air make-up unitb. around doors and windowsc. through ventilationd. because of street traffic


18. The main valve in a 4-way reversing valve is moved by pressure created by ____.a. refrigerant boiling in the coilb. pressure reduction in the condenserc. change in the action of the metering device

d. low and high side pressure difference


19. An advantage of a "series flow" configuration of ground loops is ____.a. smaller diameter pipesb. ease of removing trapped airc. lower installation costsd. less antifreeze is required


20. If the wet-bulb and dry-bulb temperature are both 80°F, what is the humidity?a. 0%b. 50%c. 75%d. 100%


21. When the water and refrigerant in a heat exchanger flow in opposite directions, it is referred to as ____.a. countersinkb. parallel flowc. counter flowd. bias flow


22. To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is ____.a. light flexible hoseb. heavy duty rubber gauge linec. copper tubed. garden hose


23. The suction line is connected between the ____.a. inside and outside coil outlets

b. inside and outside metering devicesc. compressor and the defrost relayd. compressor, accumulator, and reversing valve


24. A fresh air intake is necessary to keep the indoor air from becoming ____.a. too humidb. superheatedc. oxygen starved and stagnantd. too dry


25. To pull a vacuum means to ____.a. raise the pressure in a refrigeration systemb. lower the pressure in a refrigeration system below atmosphericc. allow refrigerant to escape into the atmosphered. condense the gas in the system


26. If the dry-bulb temperature is 93°F and the wet-bulb temperature is 60°F, what is the specific volume of the air?a. 14.0 ft3/lbb. 14.0 lb/ft3

c. 10 lb/ft3

d. 10 ft3/lb


27. The wet-bulb depression is ____.a. the difference between the dry-bulb and wet-bulb temperaturesb. the same as the wet-bulb temperaturesc. the same as the dry-bulb temperaturesd. when the air is saturated with moisture


28. Which of the following represents the lowest vacuum?a. 10 psia

b. 5" Hg VACc. 5 psigd. 1000 microns


29. The dew-point temperature is the ____.a. temperature when the air is saturated with moistureb. temperature when the moisture begins to condense out of the airc. difference between the dry-bulb and wet-bulb temperaturesd. temperature of the air at 50% relative humidity


30. The hot gas line is always connected between the ____.a. compressor and the condenserb. reversing valve and the condenserc. reversing valve and the accumulatord. compressor and the reversing valve


31. Fractionation occurs when ____.a. some of a blended refrigerant evaporates or condenses before the

rest of the blendb. when only a fraction of the total charge has been added to a systemc. the operating pressures of a system increased. Both a and c


32. An air-to-air heat pump would least likely be seen in ____.a. Floridab. Mainec. Hawaiid. Mexico


33. What is the temperature differential between water in and water out of a heat exchanger that has transferred 50,000 Btu/h? The flow rate is 10

gallons per minute.a. 10°b. 20°c. 50°d. 5°


34. When charging a system with vapor refrigerant from a refrigerant cylinder the cylinder will become ____.a. coldb. very warmc. the same temperature as the ambient air


35. Noncondensable gases ____.a. are desirable in a refrigeration systemb. are undesirable in a refrigeration systemc. condense readily under normal atmospheric conditionsd. help in pulling a vacuum


36. All air characteristics charts and tables are based on a sea level pressure of ____.a. 29.41" Hgb. 29.69" Hgc. 29.86" Hgd. 29.92" Hg


37. A multiple evacuation means that ____.a. you connect three vacuum pumps simultaneously to a refrigeration

system and pull a vacuumb. you pull a vacuum on three different systems at the same timec. you pull a vacuum on a refrigeration system more than once,

allowing refrigerant or nitrogen into the system between each procedure

d. there must be more than one system operating before a vacuum can be pulled


38. In a closed-loop system, the plastic water pipes that are buried in the Earth are called ____.a. ground loopsb. thermal loopsc. water loopsd. both a and c


39. The best method of leak checking is when the refrigeration system is ____.a. in a vacuumb. open to the atmospherec. operating with all fans activatedd. standing with dry nitrogen pressure of 150 psig in the system


40. When charging a refrigeration system with a near-azeotropic mixture, what must be done to prevent liquid from entering the system?a. Charge only as a vapor through the high side.b. Charge only liquid through the high side.c. Charge as a liquid through the low side using a restrictor.d. Charge as a vapor through the low side using a resistor.


41. The dry-bulb temperature is the ____.a. same as the wet-bulb temperatureb. total of the sensible and latent heatc. sensible heat level of the aird. sensible heat less the humidity


42. The hot gas line from the heat pump's compressor can be used to ____.a. cool down the condenserb. heat domestic waterc. keep the well water from freezing

d. both a and c


43. If 22 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 24 lb. 12 oz. before any is added, what will be the supply cylinder weight after the system has been charged?a. 22 lb. 12 oz.b. 22 lb. 6 oz.c. 23 lb. 8 oz.d. 23 lb. 6 oz.


44. Charging a refrigeration system refers to ____.a. removing refrigerant from a systemb. adding refrigerant to a systemc. cleaning the refrigerantd. vaporizing the refrigerant


45. What prevents cold air from being circulated to the heated space during the defrost cycle?a. The auxiliary heater turns on to "temper" the air.b. All of the dampers close automatically.c. The indoor fan motor turns off.d. Both a and b are correct.


46. If a critically charged refrigeration system is over charged, which of the following is a likely result?a. increased cooling capacityb. reduced compressor discharge temperaturec. increased system efficiencyd. increased operating pressures


47. When moisture is present in a refrigeration system, it will react with the

refrigerant and the oil to form ____.a. carbon dioxideb. acidc. carbon monoxided. all of the above


48. What is the most accurate instrument for checking a deep vacuum?a. compound gaugeb. mercury "U" tube manometerc. mercury barometerd. electronic vacuum gauge


49. Many coaxial heat exchangers are made of ____.a. steelb. aluminumc. nickeld. cupro-nickel


50. When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed ____.a. upside downb. right side upc. on its side


True/FalseIndicate whether the sentence or statement is true or false.

51. Air entering a refrigerant system can eventually lead to compressor failure.

ANSWER: TPOINTS: 0 / 1

52. In a closed-loop system, the same fluid (water or water and antifreeze) will

absorb heat from the ground in the winter and reject the heat to the ground in the summer.


53. Introduction of forced ventilation in the winter heating season helps to raise the humidity level.

ANSWER: FPOINTS: 0 / 1

54. The maximum recommended pressure for leak testing is 150 psig.


55. One good feature of an electronic charging scale is that it counts upward as refrigerant is removed, to tell the technician how much refrigerant was used.


56. Using a restrictor, liquid refrigerant can be charged into the low-side of the system with the system operating.


57. It is common for the outdoor unit to ice-up when the heat pump is operated in the cooling mode.


58. It is possible to have a leak-free system when under a vacuum but still leak when the system pressure is above atmospheric.


59. The quickest method to charge a system is to charge only vapor.


60. TX valves used in air conditioning units and heat pumps are interchangeable as long as they are the same size and for the same refrigerant.


61. When adding refrigerant in vapor form to a refrigeration system, the system motor/compressor assembly is running.


62. Glide is the range of temperatures/pressures in which a blended refrigerant will condense.


63. The main difference between troubleshooting a geothermal heat pump and an air-to-air heat pump is the method of obtaining needed temperatures.


64. When adding refrigerant in liquid form into the high-side of the system, the system motor/compressor assembly is running.


65. The human body is comfortable when the heat produced in the body is equal to the heat lost to the surroundings.


66. In a heat pump system, the indoor and outdoor coils are almost the same size.


67. The oil in a vacuum pump should be changed after each time it is used.


68. While under a deep vacuum, any liquid water under the oil in the motor-compressor assembly can be removed by operating the compressor motor for several seconds without any adverse effect on the system.


69. Temperature, quantity, and cleanliness are three important factors that should be addressed when referring to water quality.


70. Since the Earth's crust is cooler than the air during the summer, it can be used to accept air conditioning heat loads.


71. In order to prevent water contamination, wells used for geothermal heat pump systems are grouted.


72. On a geothermal heat pump, it is possible for scale to build up inside the refrigerant lines.


73. When brazing a 4-way reversing valve, heat absorbing paste should be placed around the body of the valve to minimize the chance of internal damage to the valve.


74. A manufacturer's charging chart may be used when available to determine the correct charge for a system.


75. When a geothermal heat pump is in the cooling mode, the ground loop is where the heat from the system is rejected.


CompletionComplete each sentence or statement.

76. The indoor coil acts as the ____________________ in the summer and as the ____________________in the winter.

RESPONSE:ANSWER: evaporator, condenserPOINTS: 0 / 1

77. Only two substances should be in the refrigeration system for proper operation. They are ____________________ and ____________________.

RESPONSE:ANSWER: refrigerant, oilPOINTS: 0 / 1

78. When a heat pump is supplying as much heat as the load requires and is operating continuously, it is at what is called the ____________________.

RESPONSE:ANSWER: balance pointPOINTS: 0 / 1

79. When electric auxiliary heat is used with a heat pump, the best location of the inside coil is ____________________ the auxiliary heat unit.

RESPONSE:ANSWER: beforePOINTS: 0 / 1

80. The sensing element of a micron gauge must always be mounted with the fitting at the ____________________.

RESPONSE:ANSWER: bottomPOINTS: 0 / 1

81. When the dry-bulb and wet-bulb temperatures are the same, the relative humidity of the air is ____________________%.

RESPONSE:ANSWER: 100POINTS: 0 / 1

82. Air is primarily made up of ____________________ and ____________________.

RESPONSE:ANSWER: nitrogen, oxygenPOINTS: 0 / 1

83. Geothermal heat pumps will ____________________ heat from the Earth and transfer it to the conditioned space in the winter and ____________________ the heat that is absorbed from the conditioned space in the summer to the Earth.

RESPONSE:ANSWER: remove, transfer or

remove, rejectPOINTS: 0 / 1

84. The efficiency of a heat pump operating in the heat mode tends to ____________________ as the outside air temperature drops.

RESPONSE:ANSWER: decreasePOINTS: 0 / 1

85. When thermostatic expansion valves are used on heat pump systems, _________________________ thermal bulbs are most common in order to prevent the valve's diaphragm from rupturing.

RESPONSE:ANSWER: vapor charged or

limited charged orcritically charged

POINTS: 0 / 1

86. ____________________ grains of moisture equals one pound of water.

RESPONSE:ANSWER: 7,000POINTS: 0 / 1

87. When the refrigerant cylinder is connected to an operating system, the pressure in the cylinder will be ____________________ than the suction pressure of the system.

RESPONSE:ANSWER: higherPOINTS: 0 / 1

88. Before deciding to purchase or install an open-loop system, the ____________________ must be evaluated first.

RESPONSE:ANSWER: water qualityPOINTS: 0 / 1

89. When fresh air is introduced through the air handling system, the process is called ____________________ ventilation.

RESPONSE:ANSWER: forcedPOINTS: 0 / 1

90. A "dedicated" geothermal well is part of a(n) ____________________ system.

RESPONSE:ANSWER: closed-loopPOINTS: 0 / 1

91. If the dry-bulb temperature is 76°F and the wet-bulb temperature is 68°F, the wet-bulb depression is ____________________°F.

RESPONSE:ANSWER: 8POINTS: 0 / 1

92. A(n) ____________________ system uses water from the Earth and then, after the cycle is complete, returns the water to the Earth.

RESPONSE:ANSWER: open-loopPOINTS: 0 / 1

93. Sludge is produced when ____________________, ____________________, and ____________________ are present in the

system.

RESPONSE:ANSWER: moisture, acid, oilPOINTS: 0 / 1

94. Four types of group loop configurations are ____________________, ____________________, ____________________, and ____________________.

RESPONSE:ANSWER: vertical, horizontal, slinky, pond or

vertical, horizontal, slinky, lakePOINTS: 0 / 1

95. The difference between wet-bulb and dry-bulb temperature is called _________________________.

RESPONSE:ANSWER: wet-bulb depressionPOINTS: 0 / 1

96. In time-temperature defrost controls, the temperature that actuates the control is the temperature of the ____________________.

RESPONSE:ANSWER: outside coilPOINTS: 0 / 1

97. When oil or gas auxiliary heat is used with a heat pump, the heat pump coil must be located in the _________________________ of the furnace.

RESPONSE:ANSWER: outlet air streamPOINTS: 0 / 1

98. The temperature sensitive resistor commonly used on vacuum gauges is called a ____________________.

RESPONSE:ANSWER: thermistorPOINTS: 0 / 1

99. ____________________ microns is equal to 1 mm Hg.

RESPONSE:

ANSWER: One thousandPOINTS: 0 / 1

100. If a heat pump is not capable of handling the heat load, an ______________________________ will be added to help handle the load.

RESPONSE:ANSWER: auxiliary heat sourcePOINTS: 0 / 1

Heat Pumps

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