Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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A micron gauge is used to measure ____.
a. | atmospheric pressures at high altitudes | b. | atmospheric
pressures at sea level | c. | absolute pressures below 1 mm
Hg | d. | high pressure in a refrigeration system |
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2.
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Moisture in a liquid state must be ____ before it can be removed with a vacuum
pump.
a. | vaporized | b. | condensed | c. | cooled | d. | solidified |
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3.
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Comfort can be described as the gentle balance between ____.
a. | air cleanliness, air movement, temperature, and humidity | b. | air velocity, air
cleanliness, humidity, and air movement | c. | air speed, air velocity, temperature, and
humidity | d. | acceleration, air cleanliness, filtration, and
humidity |
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4.
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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. |
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5.
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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. |
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6.
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A graduated cylinder charging device is a device that ____.
a. | measures refrigerant by volume for precise refrigerant charging | b. | has a compensation
dial for adjusting for the temperature of the refrigerant | c. | often has a heater
to keep the refrigerant temperature from dropping when refrigerant is released into the
system | d. | all of the above |
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7.
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The generalized comfort chart can be used as a basis to ____.
a. | determine combinations of temperature and humidity to produce comfort in summer and
winter | b. | study air and its properties | c. | determine the amount of fresh air make up
necessary for comfort | d. | none of the
above |
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8.
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The density of air is the ____.
a. | amount of moisture in the air | b. | amount of movement in the air per cubic
foot | c. | weight of the air per cubic foot | d. | combination of the temperature and pressure of
the air |
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9.
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Of the heat produced in the human body, which is by perspiration?
a. | conduction | b. | convection | c. | radiation | d. | evaporation |
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10.
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Refrigerant in vapor form is normally put into the system through the
____.
a. | liquid line | b. | suction line | c. | hot gas
line | d. | liquid return line |
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11.
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Termination of the defrost cycle occurs when the liquid off the outside coil
reaches ____.
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12.
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A compound gauge ____.
a. | indicates pressures above 14.696 psia | b. | indicates pressures in inches Hg below
atmospheric pressure | c. | is one of two gauges on a typical gauge
manifold | d. | all of the above |
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13.
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The wet-bulb temperature ____.
a. | is the same as the wet-bulb depression | b. | is the saturation pressure | c. | takes into account
the moisture content of the air | d. | is always higher than the dry-bulb
temperature |
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14.
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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 pressure | d. | the high pressure gauge will read the suction
pressure and the low pressure will read discharge pressure |
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15.
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A pressure-temperature defrost control is activated by the ____.
a. | difference of the pressure in the fan compartment and the temperature of the
coil | b. | difference in pressure between the outdoor pressure and the fan discharge
pressure | c. | difference in the pressure of the air through the outdoor coil | d. | difference in
pressure of the refrigerant in the condenser and the pressure in the
coil |
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16.
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What is the dew-point temperature if the wet-bulb temperature is 65°F and
the dry-bulb temperature is 100°F?
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17.
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Infiltration is the term used when referring to the air entering a structure
____.
a. | through an air make-up unit | b. | around doors and windows | c. | through
ventilation | d. | because of street traffic |
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18.
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The main valve in a 4-way reversing valve is moved by pressure created by
____.
a. | refrigerant boiling in the coil | b. | pressure reduction in the
condenser | c. | change in the action of the metering device | d. | low and high side
pressure difference |
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19.
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An advantage of a "series flow" configuration of ground loops is
____.
a. | smaller diameter pipes | b. | ease of removing trapped
air | c. | lower installation costs | d. | less antifreeze is
required |
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20.
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If the wet-bulb and dry-bulb temperature are both 80°F, what is the
humidity?
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21.
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When the water and refrigerant in a heat exchanger flow in opposite directions,
it is referred to as ____.
a. | countersink | b. | parallel flow | c. | counter
flow | d. | bias flow |
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22.
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To insure accurate testing, the best material to use for connecting lines to the
vacuum pump and gauge set is ____.
a. | light flexible hose | b. | heavy duty rubber gauge
line | c. | copper tube | d. | garden hose |
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23.
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The suction line is connected between the ____.
a. | inside and outside coil outlets | b. | inside and outside metering
devices | c. | compressor and the defrost relay | d. | compressor, accumulator, and reversing
valve |
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24.
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A fresh air intake is necessary to keep the indoor air from becoming
____.
a. | too humid | b. | superheated | c. | oxygen starved and
stagnant | d. | too dry |
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25.
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To pull a vacuum means to ____.
a. | raise the pressure in a refrigeration system | b. | lower the pressure
in a refrigeration system below atmospheric | c. | allow refrigerant to escape into the
atmosphere | d. | condense the gas in the system |
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26.
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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/lb | b. | 14.0 lb/ft3 | c. | 10
lb/ft3 | d. | 10
ft3/lb |
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27.
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The wet-bulb depression is ____.
a. | the difference between the dry-bulb and wet-bulb temperatures | b. | the same as the
wet-bulb temperatures | c. | the same as the dry-bulb
temperatures | d. | when the air is saturated with moisture |
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28.
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Which of the following represents the lowest vacuum?
a. | 10 psia | b. | 5" Hg VAC | c. | 5
psig | d. | 1000 microns |
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29.
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The dew-point temperature is the ____.
a. | temperature when the air is saturated with moisture | b. | temperature when the
moisture begins to condense out of the air | c. | difference between the dry-bulb and wet-bulb
temperatures | d. | temperature of the air at 50% relative humidity |
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30.
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The hot gas line is always connected between the ____.
a. | compressor and the condenser | b. | reversing valve and the
condenser | c. | reversing valve and the accumulator | d. | compressor and the reversing
valve |
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31.
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Fractionation occurs when ____.
a. | some of a blended refrigerant evaporates or condenses before the rest of the
blend | b. | when only a fraction of the total charge has been added to a
system | c. | the operating pressures of a system increase | d. | Both a and
c |
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32.
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An air-to-air heat pump would least likely be seen in ____.
a. | Florida | b. | Maine | c. | Hawaii | d. | Mexico |
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33.
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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.
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34.
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When charging a system with vapor refrigerant from a refrigerant cylinder the
cylinder will become ____.
a. | cold | b. | very warm | c. | the same temperature
as the ambient air |
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35.
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Noncondensable gases ____.
a. | are desirable in a refrigeration system | b. | are undesirable in a
refrigeration system | c. | condense readily under normal atmospheric
conditions | d. | help in pulling a vacuum |
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36.
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All air characteristics charts and tables are based on a sea level pressure of
____.
a. | 29.41" Hg | b. | 29.69" Hg | c. | 29.86"
Hg | d. | 29.92" Hg |
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37.
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A multiple evacuation means that ____.
a. | you connect three vacuum pumps simultaneously to a refrigeration system and pull a
vacuum | b. | you pull a vacuum on three different systems at the same time | c. | 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 |
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38.
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In a closed-loop system, the plastic water pipes that are buried in the Earth
are called ____.
a. | ground loops | b. | thermal loops | c. | water
loops | d. | both a and c |
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39.
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The best method of leak checking is when the refrigeration system is
____.
a. | in a vacuum | b. | open to the atmosphere | c. | operating with all
fans activated | d. | standing with dry nitrogen pressure of 150 psig in the
system |
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40.
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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. |
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41.
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The dry-bulb temperature is the ____.
a. | same as the wet-bulb temperature | b. | total of the sensible and latent
heat | c. | sensible heat level of the air | d. | sensible heat less the
humidity |
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42.
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The hot gas line from the heat pump's compressor can be used to
____.
a. | cool down the condenser | b. | heat domestic water | c. | keep the well water
from freezing | d. | both a and c |
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43.
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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. |
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44.
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Charging a refrigeration system refers to ____.
a. | removing refrigerant from a system | b. | adding refrigerant to a
system | c. | cleaning the refrigerant | d. | vaporizing the
refrigerant |
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45.
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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. |
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46.
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If a critically charged refrigeration system is over charged, which of the
following is a likely result?
a. | increased cooling capacity | b. | reduced compressor discharge
temperature | c. | increased system efficiency | d. | increased operating
pressures |
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47.
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When moisture is present in a refrigeration system, it will react with the
refrigerant and the oil to form ____.
a. | carbon dioxide | b. | acid | c. | carbon
monoxide | d. | all of the above |
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48.
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What is the most accurate instrument for checking a deep vacuum?
a. | compound gauge | b. | mercury "U" tube
manometer | c. | mercury barometer | d. | electronic vacuum
gauge |
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49.
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Many coaxial heat exchangers are made of ____.
a. | steel | b. | aluminum | c. | nickel | d. | cupro-nickel |
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50.
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When charging liquid refrigerant from a single valve supply cylinder, the
cylinder is placed ____.
a. | upside down | b. | right side up | c. | on its
side |
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True/False
Indicate whether the
sentence or statement is true or false.
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51.
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Air entering a refrigerant system can eventually lead to compressor
failure.
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52.
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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.
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53.
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Introduction of forced ventilation in the winter heating season helps to raise
the humidity level.
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54.
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The maximum recommended pressure for leak testing is 150 psig.
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55.
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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.
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56.
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Using a restrictor, liquid refrigerant can be charged into the low-side of the
system with the system operating.
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57.
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It is common for the outdoor unit to ice-up when the heat pump is operated in
the cooling mode.
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58.
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It is possible to have a leak-free system when under a vacuum but still leak
when the system pressure is above atmospheric.
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59.
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The quickest method to charge a system is to charge only vapor.
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60.
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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.
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61.
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When adding refrigerant in vapor form to a refrigeration system, the system
motor/compressor assembly is running.
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62.
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Glide is the range of temperatures/pressures in which a blended refrigerant will
condense.
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63.
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The main difference between troubleshooting a geothermal heat pump and an
air-to-air heat pump is the method of obtaining needed temperatures.
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64.
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When adding refrigerant in liquid form into the high-side of the system, the
system motor/compressor assembly is running.
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65.
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The human body is comfortable when the heat produced in the body is equal to the
heat lost to the surroundings.
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66.
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In a heat pump system, the indoor and outdoor coils are almost the same
size.
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67.
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The oil in a vacuum pump should be changed after each time it is used.
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68.
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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.
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69.
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Temperature, quantity, and cleanliness are three important factors that should
be addressed when referring to water quality.
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70.
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Since the Earth's crust is cooler than the air during the summer, it can be
used to accept air conditioning heat loads.
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71.
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In order to prevent water contamination, wells used for geothermal heat pump
systems are grouted.
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72.
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On a geothermal heat pump, it is possible for scale to build up inside the
refrigerant lines.
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73.
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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.
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74.
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A manufacturer's charging chart may be used when available to determine the
correct charge for a system.
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75.
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When a geothermal heat pump is in the cooling mode, the ground loop is where the
heat from the system is rejected.
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Completion
Complete each
sentence or statement.
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76.
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The indoor coil acts as the ____________________ in the summer and as the
____________________in the winter.
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77.
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Only two substances should be in the refrigeration system for proper operation.
They are ____________________ and ____________________.
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78.
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When a heat pump is supplying as much heat as the load requires and is operating
continuously, it is at what is called the ____________________.
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79.
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When electric auxiliary heat is used with a heat pump, the best location of the
inside coil is ____________________ the auxiliary heat unit.
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80.
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The sensing element of a micron gauge must always be mounted with the fitting at
the ____________________.
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81.
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When the dry-bulb and wet-bulb temperatures are the same, the relative humidity
of the air is ____________________%.
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82.
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Air is primarily made up of ____________________ and
____________________.
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83.
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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.
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84.
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The efficiency of a heat pump operating in the heat mode tends to
____________________ as the outside air temperature drops.
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85.
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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.
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86.
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____________________ grains of moisture equals one pound of water.
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87.
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When the refrigerant cylinder is connected to an operating system, the pressure
in the cylinder will be ____________________ than the suction pressure of the system.
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88.
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Before deciding to purchase or install an open-loop system, the
____________________ must be evaluated first.
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89.
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When fresh air is introduced through the air handling system, the process is
called ____________________ ventilation.
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90.
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A "dedicated" geothermal well is part of a(n) ____________________
system.
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91.
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If the dry-bulb temperature is 76°F and the wet-bulb temperature is
68°F, the wet-bulb depression is ____________________°F.
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92.
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A(n) ____________________ system uses water from the Earth and then, after the
cycle is complete, returns the water to the Earth.
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93.
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Sludge is produced when ____________________, ____________________, and
____________________ are present in the system.
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94.
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Four types of group loop configurations are ____________________,
____________________, ____________________, and ____________________.
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95.
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The difference between wet-bulb and dry-bulb temperature is called
_________________________.
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96.
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In time-temperature defrost controls, the temperature that actuates the control
is the temperature of the ____________________.
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97.
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When oil or gas auxiliary heat is used with a heat pump, the heat pump coil must
be located in the _________________________ of the furnace.
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98.
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The temperature sensitive resistor commonly used on vacuum gauges is called a
____________________.
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99.
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____________________ microns is equal to 1 mm Hg.
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100.
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If a heat pump is not capable of handling the heat load, an
______________________________ will be added to help handle the load.
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