Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Trane Reciprocating Refrigeration
Questions and Answers
1. When the temperature difference between the refrigerant gas and the water increases the capacity of the
condenser is _____________?
A Decreased
B Static
C Increased
D Transferred
2. High efficiency forced or induced draft cooling towers will cool the condenser water to a point _________?
A Within 5 to 8 degrees of the prevailing wet bulb temperature
B 10 degrees below boiling
C 10 degrees above boiling
D Within 5 to 8 degrees of the prevailing dry bulb temperature
3. A straight induction motor is a/an_____________?
A Squirrel Cage Motor
B Total Enclosed Motor
C Open Motor
D Totally Enclosed Fan-Cooled Motor
4. When testing a system for leaks, connect to the frontseat port of the compressor discharge valve a cylinder
of______________?
A Acetylene
B Oxygen (oil-free)
C Oil-pumped dry nitrogen
D Dry pumped oil free nitrogen
5. The superheat setting for most air conditioning systems is______________?
A 10F
B Approximately 8 to 11 F
C 12F
D Approximately 12 to 15 F
6. The type of cooling coils rated on the basis of approximately 10 degrees superheat is_______________?
A Direct thermo expansion
B Direct Expansion
C Indirect thermo expansion
D Indirect Expansion
Copyri
ght
Rob Este
ll
7. The closing of the normally open second auxiliary contacts of the fan or chilled water pump starter completes
the ______________________?
A Low voltage control circuit to the temperature controller
B High voltage control circuit to the temperature controller
C Low voltage control circuit to the condenser
D Low voltage control circuit to the fan
8. Within horizontal refrigerant gas carrying lines the minimum gas velocity is ________________?
A 400 feet per minute
B 750 feet per minute
C 500 feet per minute
D 650 feet per minute
9. The motor enclosure in which air is circulated directly over the motor windings is______________?
A Slip Ring Motor
B Splash-proof Motor
C Explosion-proof Motor
D Open Motor
10. An additional load is placed on the condenser when ___________?
A Heat is lost by the suction lines
B Heat is maintained on the suction lines
C Heat is gained by the suction lines
D Chilling is gained by the expansion line
11. For leak testing it is recommended dry nitrogen be charged to the system through the valve of a/an ______?
A Gauge manifold
B Intake manifold
C Pressure gauge
D Directional manifold
12. To wire a dual voltage motor for lower voltage (230 volt) full winding start, the windings are __________?
A Wired in series
B Wired in parallel
C Overlapped
D Omni-directional
13. The system required for a single discharge line sized to maintain the required 1,000 feet per minute
minimum load gas velocity within the hot gas riser is__________________?
A A single riser system
B A triple riser system
C A double riser system
D Bypass gate valve riser system
Copyri
ght
Rob Este
ll
14. The amount of friction loss within a pipe is__________________?
A Mineral content of the water
B Dependent upon the condition of the pipe and the velocity of the water
C Absorption capacity of the pipe and the velocity
D Size of the pipe and the condition of the pipe
15. An instrument for measuring temperature is a/an ______________?
A Thermometer
B Thermostat
C Dry Bulb
D Wet Bulb
16. If load variations are wide and subject to rapid changes expansion valves should be set for superheats from?
A 10 to 15 degrees
B 10 to 12 degrees
C 12 to 15 degrees
D 8 to 12 degrees
17. When testing for leaks, the nitrogen cylinder pressure regulator setting is_______________?
A 150 psig
B 125 psig or the leak test pressure specified by local code.
C 130 psig
D 150 psig or the leak test pressure specified by local code.
18. The present concept of a cooling tower was reached when?
A Electricity was available to run the system
B A fan that either pushed or pulled the air through the tower was added
C A condenser was added to the system
D Blow-down control was obtained
19. A controller producing a modulated control signal is a/an_________________?
A Two-Position Controller
B On-Off Controller
C Proportional Controller
D Pneumatic Controller
20. Based on 40 F suction and 105 F condensing liquid lines 40 feet in length connected to a 148 tons with a
total pressure drop 5 psi, the copper tube size needed when using R-22 is ___________?
A 1 3/8 inch
B 1 5/8 inch
C 1 3/4 inch
D 1 1/8 inch
Copyri
ght
Rob Este
ll
21. Given: Saturated refrigerant-502 having a 152.32 psia and a 137.62 psig the gas temperature is?
A 78 F
B 60 F
C 76 F
D 70 F
22. The boiling point of liquid and the condensing temperature of vapor are _______________?
A Exactly the same at any one pressure is
B Always different regardless of temperature
C Always the same at any given fluid level
D Co-dependent
23. Given: Saturated refrigerant-22 with a temperature of 106F and a psia of 228.50. The psig is?
A 201.76
B 228.50
C 213.81
D 207.72
24. Given: Suction gas velocities for refrigerant-22 with a 1 5/8 inch line outside diameter, Type L copper
tubing carrying 25 tons. The gas velocity is?
A 4,500 feet per minute
B 3,000 feet per minute
C 5,000 feet per minute
D 4,000 feet per minute
25. Based on 40 F suction and 105 F condensing lines delivering liquid refrigerant from receiver to evaporator
with equivalent length of 100 feet. The copper tube size-OD-Type L to support 18.7 tons with a pressure drop
of 3 psi is when using R-22 is?
A 1 3/8 inch
B 7/8 inch
C 1 1/8 inch
D 3/4 inch
26. Liquid refrigerant may pass from the evaporator into the suction line if ______________?
A The thermostatic expansion valve is adjusted to produce too little superheat
B The thermostatic expansion valve is closed
C The thermostatic expansion valve is open
D The humidity ratio is above normal
Copyri
ght
Rob Este
ll
27. Given: Suction gas velocities for refrigerant-22 carrying 1500 feet per minute for 25 tons.
The outside diameter for type-L copper tubing should be ________________?
A 2 1/8 inches
B 3 1/8 inches
C 7/8 inches
D 2 5/8 inches
28. Given: Based on 40 F suction and 105 F condensing suction lines delivering refrigerant-22 vapor from
evaporator to compressor with equivalent length of 40 feet, total pressure
drop of 0.5 psi, the copper tube size to support 10.2 tons is __________?
A 2 1/8 inches
B 1 5/8 inches
C 1 3/8 inches
D 1 1/8 inches
29. Given: Based on 40° F suction and 105 F condensing a 7/8 inch copper tube line delivering liquid
refrigerant-22 from receiver to evaporator with equivalent length of 125 feet carrying 16.0 tons the total
pressure drop is ___________?
A 7 psi
B 2 psi
C 5 psi
D 3 psi
30. Given: Based on 40 F suction and 105 F condensing discharge lines delivering refrigerant-22 vapor from
compressor to condenser that has an equivalent length of 40 feet carrying 52.3 tons with total pressure drop of 5
psi the size copper tube size is __________?
A 3 1/8 inches
B 1 5/8 inches
C 2 1/8 inches
D 1 3/8 inches
31. Most air conditioning applications are satisfactory when the superheat is adjusted at?
A 12 to 15 F superheat
B 10 to 12 F superheat
C 8 to 10 F superheat
D 11 to 15 F superheat
32. The amount of heat produced by a motor is a function of ________________?
A Energy and humidity
B Efficiency and load
C Temperature and enthalpy
D Coil impact and resistance
Copyri
ght
Rob Este
ll
33. Methods of air cooled condenser capacity control currently used include all of the following except?
A Relay
B Damper
C Fan cycling
D Flood-back
34. Damper control is adequate for condensing ambient air temperatures down to approximately
______________ degrees Fahrenheit.
A 50
B 45
C 40
D 35
35. Gauges used for air conditioning work should be____________?
A Designed for commercial use
B Designed for refrigeration service
C Generic
D Easy to install and work with
36. Suction line is being sized for a job. Chilly Pete notes a 90 degree Fahrenheit condensing temperature and a
10 degree Fahrenheit suction temperature. Using R- 22, the suction line correction factor is?
A 1.69
B 1.49
C 1.31
D 1.29
37. When using refrigerant 12 or 22, the refrigerant piping in the system must be?
A Pre-treated
B Lubricated
C Made of refrigerant tubing which has been cleaned by the manufacturer
D Absolutely clean
38. A compressor fails to start for all of the following reasons except _______________?
A Power failure
B Low voltage
C Burned out motor
D Lack of refrigerant
Copyri
ght
Rob Este
ll
39. While troubleshooting a refrigeration system, Rob observes bubbles in the sight glass and determines the
system needs refrigerant. Rob will _______________?
A Repair or replace the valve, then charge the system
B Find and repair the leak, then charge the system
C Reset the compressor capacity control range
D Add refrigerant, then run a test
40. A device used to measure gas pressures both above and below atmospheric pressure is called
a gauge?
A Pressure
B Multi-purpose
C Convex
D Compound
41. Given R22 at 196 PSIG, the temperature of saturated refrigerant in the receiver is __________?
A 95 degrees
B 136 degrees
C 130 degrees
D 100 degrees
42. Given R 22 at 260 PSIG. The refrigerant leaves the condenser at 114 degrees Fahrenheit. The refrigerant is
subcooled ________?
A 4 degrees
B 6 degrees
C 8 degrees
D 10 degrees
43. A walk-in freezer uses R-22 refrigerant. The low pressure cutout is at 12.5 PSIG. To lower the temperature
6 degrees, the low pressure cutout must be set at ___________?
A 9.0
B 10.0
C 11.0
D 12.0
44. The temperature is 42 degrees Fahrenheit. The contractor is using R-22. Suction pressure should be ______?
A 68 PSIA
B 86 PSIA
C 98 PSIA
D 105 PSIA
Copyri
ght
Rob Este
ll
45. Voltage readings were taken with the following results: 231 V, 227V and 233V. The percent of variance is
_____________?
A 1.4
B 1.75
C 1.9
D 2.0
46. A storage tank contains R-22. The outside air temperature is 140 degrees Fahrenheit. The gage pressure is
___________?
A Less than 250
B Between 250 and 300
C Between 300 and 350
D More than 350
47. Refrigeration must be gas tight because?
A The system will gain moisture
B The unit will not work
C The gas is poisonous
D The liquid will leave the condenser at saturation
48. A refrigeration system uses R-12. The condensing temperature is 125 degrees Fahrenheit. The operating
pressure of the condenser should be _________?
A 140 PSIG
B 155 PSIG
C 169 PSIG
D 183 PSIG
49. The 1 3/8 inch non-ferrous piping used for R-22 is 60 feet long. There will be one (1) sight glass, two (2)
short radius ells, one (1) globe valve and one (1) long radius ell. The total equivalent length is?
A Less than 100 feet
B Between 100 and 150 feet
C Between 150 and 200 feet
D More than 200 feet
50. When a control mechanism is used on an air conditioning system, the simplest control action is
_________________?
A A switch
B Two position or on-off
C Proportioning
D The single-function on-off control
Copyri
ght
Rob Este
ll
51. A normal start-up sequence of an R-22 system is initiated at psig condensing pressure when
the motor starts to open the blades.
A 155
B 165
C 175
D 185
52. Starters that make use of separate circuits in the motor to reduce the starting current are called starters.
A Full winding
B Across-the-line
C Winding
D Part winding
53. Compound gauges used for refrigeration service should be calibrated from 0 psi pressure to no less
than psi above the normal working suction and discharge pressures of the system.
A 50 to 75
B 50 to 100
C 75 to 100
D 75 to 110
54. Refrigerant 12 and 22 are solvents.
A Poor
B Fair
C Good
D Excellent
55. The amount of friction loss in a water pipe is dependent upon the __________?
A Pipe size
B Pipe length
C The condition of the pipe and the velocity of the water
D The condition of the pipe, the course taken by the pipe run and the velocity of the water
56. The recommended action to take when a compressor freezes due to a damaged mechanism is to
the compressor?
A Overhaul the compressor
B Replace
C Repair or replace
D Clean and check
Copyri
ght
Rob Este
ll
57. Bubbles in the sight glass and a lack of refrigerant indicate the ________________?
A Discharge pressure is too high
B Discharge pressure is too low
C Suction pressure is too high
D Suction pressure is too low
58. Given R-12 at 196 PSIG, the temperature of saturated refrigerant in the receiver is __________?
A 95 degrees
B 136 degrees
C 130 degrees
D 100 degrees
59. Given R-12 at 181 PSIG. The refrigerant leaves the condenser at 124 degrees Fahrenheit. The refrigerant is
subcooled __________?
A 4 degrees
B 6 degrees
C 8 degrees
D 10 degrees
60. A walk-in freezer uses R-22 refrigerant. The low pressure cutout is at 10 PSIG. To lower the temperature 6
degrees, the low pressure cutout must be set at ___________?
A 6.8
B 5.8
C 7.9
D 9.0
61. The temperature is 16 degrees Fahrenheit. The contractor is using R-22. Suction pressure should be
_______________?
A 71 PSIA
B 86 PSIA
C 38 PSIA
D 53 PSIA
62. Voltage readings were taken with the following results: 226V, 230V and 241V.The percent of variance is
_______________?
A 1.5
B 2
C 3.3
D 3.7
Copyri
ght
Rob Este
ll
63. A storage tank contains R-12. The outside air temperature is 130 degrees Fahrenheit. The gage pressure is
__________?
A Less than 175
B Between 175 and 185
C Between 185 and 195
D More than 195
64. A refrigeration system uses R-22. The condensing temperature is 126 degrees Fahrenheit. The operating
pressure of the condenser should be _________?
A 296 PSIG
B 281 PSIG
C 169 PSIG
D 183 PSIG
65. The 1 5/8 inch non-ferrous piping used for R-22 is 40 feet long. There' will be one (1) sight glass, two (2)
short radius ells, one (1) globe valve and one (1) long radius ell. The total equivalent length is ____________?
A Less than 100 feet
B Between 100 and 150 feet
C Between 150 and 200 feet
D More than 200 feet
66. R-502 at 46 degrees Fahrenheit has a gage reading of_________?
A 74.3
B 89.0
C 82.3
D 92.1
67. When making copper-to-steel joints, the contractor should use __________?
A Sil-fos
B Silver solder
C Crocus solder
D Acid flux
68. The service technician notices the gage pressure for Refrigerant-22 is 243 degrees. The temperature should
be how many degrees Fahrenheit?
A 114
B 115
C 116
D 117
Copyri
ght
Rob Este
ll
69. A main control for air cooled condensers is through the use of a control.
A Damper
B Flyback
C Multiflex
D Constant pressure
70. The heat required to change a liquid to a gas is the __________?
A Latent heat of vaporization
B Latent heat of fusion
C Latent heat of fission
D Latent heat of evaporation
71. Useable oil pressure is determined by _____________?
A Bore stroke analysis
B The size of the piston and the force of the ram
C Oil pressure plus suction pressure
D Oil pressure minus suction pressure
72. A NEMA rated enclosed motor with a Class Insulation factor of F would have a maximum surface
temperature of degrees Fahrenheit.
A 273
B 265
C 309
D 335
73. Leak testing should be _______________?
A An on-going process
B Done before the pipe is insulated
C The first check of the system
D Done visually prior to start-up
74. Normally the solenoid oil valves are controlled by _______________?
A The multi-stage electric thermostat
B The de-energizing valve
C A solenoid valve timing switch
D A hemi-stat reversing control valve
75. The minimum hot gas velocity for the vertical riser should be not less than feet per minute.
A 500
B 1,000
C 1,500
D 2,000
Copyri
ght
Rob Este
ll
76. When adding compressor oil, the contractor should?
A Use one additional pint of refrigerant for each ten pounds of oil
B Use one additional pint of oil for each ten pounds of refrigerant
C Pump the oil into the compressor crankcase while the system is shutdown
D Check to see that the oil is filling the sight glass
77. The hot gas line is the line?
A Compressor to the condenser
B Condenser to the evaporator
C Evaporator to the compressor
D Compressor to the evaporator
78. When needing to install a 15 ton unit using R-22, at 100 feet developed length with a 3 psi drop from the
receiver to the evaporator, the size Type "L" copper line to use with a suction of 40F and 105 F condensing is
inches.
A 7/8
B 1
C 1 1/8
D 1 3/8
79. To stabilize the suction pressure and temperature throughout, compressors used in large systems are
generally equipped with cylinder __________?
A Sequence monitoring
B Unloading control
C Timing mechanisms
D Withdrawal blocks
80. One of the nice things about a trap is _________?
A The filter effect on the fluid
B The aid in allowing the oil to start its climb up the suction and hot gas risers
C The minimum horizontal dimension required for cutting down the elbows
D The accumulation of oil drained from the hot gas riser
81. Which of the following should never be used as a test gas?
A Dry nitrogen
B Oxygen
C Krypton
D Argon
Copyri
ght
Rob Este
ll
82. The gage reading for R-12 at 124 degrees should be ___________?
A 166.73
B 181.43
C 162.15
D 171.40
83. The contractor is reading 259.91 on the compound gage. The temperature must be lowered 18 degrees.
Using R-22 the gage reading should be?
A 210.60
B 195.91
C 201.76
D 222.42
84. The contractor is installing a single phase magnetic starter. Voltage equal to line voltage between loads T-1
and T-2 means?
A The magnetic coil is energized and the starter main contacts are open
B The magnetic coil is energized and the auxiliary contacts open
C The starter main contacts are energized and the auxiliary contacts are closed
D The magnetic coil is energized and the main contacts and auxiliary contacts are closed
85. Billy Joe obtained voltage readings of 230, 225 and 232. Billy Joe pondered and determined the voltage
imbalance was _________?
A 1.75 percent
B 1.31 percent
C 17.46 percent
D 2.941 percent
86. The R-22 discharge is 305 PSIG. The condenser pressure is 302 PSIG. Pressure at the expansion valve is
225 PSIG. The most probable cause is _________?
A Refrigerant overcharge
B Improperly sized expansion valve
C Improper superheat adjustment
D Inoperative expansion valve
87. R-22 is being sent from the evaporator to the compressor. The distance is 300 feet. The pressure drop is 2.0
psi. The copper line is 3 5/8 inches. The maximum tonnage is ________?
A 43.2
B 57
C 63
D 77.5
Copyri
ght
Rob Este
ll
88. R-22 is being delivered from the evaporator to the compressor. The distance is 360 inches. The pressure
drop is 2.0 psi. The copper line is 2 5/8 inches. The maximum tonnage is __________?
A 43.5
B 57.4
C 63.5
D 92.5
89. The HE HEC250 compressor has a condensing temperature of 115 degrees F and a suction temperature of
30 degrees F. R-22 is to be delivered 300 feet. When delivering liquid refrigerant from the receiver to the
evaporator the maximum line size with the least pressure drop is __________?
A 1 5/8 at 2 psi
B 1 3/8 at 4 psi
C 1 3/8 at 5 psi
D 1 1/8 at 8 psi
90. The suction temperature is 20 degrees F and the condensing temperature is 135 degrees F. R-22 is being
moved from the evaporator to the compressor. The distance is 300 inches. The pressure drop is 2 psi. Using a 3
5/8 inch line, the corrected tonnage should be _________?
A 63
B 94.5
C 219
D 328.5
91. The gage reading is 10.182. Refrigerant 12 is being used. To lower the temperature 8 degrees the gage
reading must be ___________?
A 5.363
B 6.264
C 20.059
D 20.960
92. The gage reading is 337.25. Using R 22, the temperature is ___________?
A 135
B 150
C 120
D 140
93. The controller containing a shaft with a series of cams is the __________?
A Potentiometer controller
B Magnetic relay controller
C Step controller
D Proportional controller
Copyri
ght
Rob Este
ll
94. Which drawing below is wired correctly for 230 volt full winding start?
A A
B B
C C
D D
95. Given an absolute pressure reading of 24.878 pounds per square inch, a pressure gage will register how
many pounds of pressure per square inch for saturated refrigerant-12?
A 10.182
B 11.243
C 12.340
D 13.471
96. The pressure gage registers pounds of pressure per square inch for saturated refrigerant-
22 at 120 degrees Fahrenheit.
A 252.94
B 259.91
C 281.63
D 289.14
97. The controller in a refrigeration system can consist of a shaft upon which is mounted a
series of cams.
A Pressure
B Proportional
C Signal
D Step
98. The pressure difference is measured by , when using oil pressure failure controls.
A Subtracting the oil pressure from the suction pressure
B A time delay mechanism
C Opposing bellows
D A computer
Copyri
ght
Rob Este
ll
99. Should the oil pressure fail to overcome opposing forces within when using the oil pressure
failure control, the timer switch will open.
A One minute
B Two minutes
C 140 seconds
D 160 seconds
100. R-22 at 48 degrees Fahrenheit has a gage reading of ____________?
A 95.4
B 80.7
C 78.2
D 78.5
101. The current starter makes use of separate circuits in the motor to reduce starting
A Across-the-line
B Autotransformer
C Part winding
D Full winding
102. After sizing the liquid line, the line is next to be sized.
A Suction
B Vapor
C Hot gas discharge
D Condenser drain
103. Assume a suction line is delivering R-22 vapor from evaporator to compressor. Given a 40 degree
Fahrenheit suction and a 105 degree Fahrenheit condensing, the tonnage recommended at a pressure drop of 2.0
psi for a 1/2 inch copper tube (0.D. Type L) 30 feet long is?
A 2.1
B 1.1
C 0.9
D 0.4
104. The flame of a halide torch will turn if a small leak is present in a refrigeration system.
A Yellow
B Bright orange
C Dense blue
D Green
Copyri
ght
Rob Este
ll
105. Allow a refrigeration system to function normally for day(s) during the initial run-in period.
A 4
B 3
C 2
D 1
106.A gage is used to measure gas pressures both above and below atmospheric pressure.
A Compound
B Discharge pressure
C Head pressure
D Liquid level
107. Given a temperature reading of minus 6 degrees Fahrenheit, a pressure gage will
register pounds of pressure per square inch for saturated refrigerant-12.
A 6.264
B 7.195
C 8.158
D 9.153
108. At 124 degrees Fahrenheit, saturated refrigerant-12 has , expressed in pounds per square
inch.
A An absolute pressure reading of 186.43
B An absolute pressure reading of 176.85
C A pressure gage reading of 166.73
D A pressure gage reading of 171.40
109. The pressure gage will register 337.25 pounds of pressure per square inch for refrigerant-
22 at degrees Fahrenheit.
A 138
B 140
C 142
D 144
110. The is well suited to the stop-start, loading and unloading control of a reciprocating
compressor.
A Duct thermostat
B Pneumatic thermostat
C Pressure controller
D Step controller
Copyri
ght
Rob Este
ll
111. The oil pump discharge pressure is sensed by one bellows while the suction pressure is sensed by another,
when using _____________?
A Oil pressure failure controls
B High/low pressure controls
C A diaphragm chamber
D A pressure controller
112. When the relief valve is tapped into the condenser, some codes require the installation of a relief valve on
the pressure side of the system.
A Low
B High
C Reverse
D Forward
113. In a refrigeration system, damper control is adequate for condensing ambient air temperature down to
approximately degrees Fahrenheit.
A 30
B 35
C 40
D 45
114. Under normal conditions, with suction temperatures , it is good practice to use a total
pressure drop of 2 psi when selecting R-12 suction lines.
A Not exceeding 50 degrees Fahrenheit
B In the 40 to 50 degree Fahrenheit range
C Around 40 to 45 degrees Fahrenheit
D In the "normal" range
115. Given a suction temperature of 10 and a conditioning temperature of 95, the suction line tonnage
correction factor for R-22 is ____________?
A 1.28
B 1.31
C 1.35
D 1.38
116. Assume a suction line is delivering R-22 vapor from evaporator to compressor. Given a 40 degree
Fahrenheit suction and a 105 degree Fahrenheit condensing, the recommended tonnage at a pressure drop of 2.0
psi for a 3 and 5/8 inch copper tube (0.D. Type L) 100 feet long is?
A 53.5
B 77.5
C 113.0
D 141.0
Copyri
ght
Rob Este
ll
117. Any increase in condensing temperature and pressure will cause a in evaporative
condenser capacity when considering the wet bulb temperature of the air supply?
A Increase
B Decrease
C Reversal
D Surcharge
118. After starting the initial run-in period for a refrigeration system, the amperage and voltage readings at each
motor should be checked to make certain the system?
A Is cooling
B Is operating at the condition established by the motor nameplate
C Is not leaking
D Has stabilized
119. Gauges used for refrigeration should be ____________?
A Calibrated before being sent to the jobsite
B Compound gauges
C Calibrated to operate at 100 psi or greater
D Calibrated to operate at any PSI
120. For liquid lines the recommended R-12 pressure drop is _______?
A 4 psi
B 3 psi
C 2 psi
D 1 psi
120. The use of oxygen as a leak test gas may cause _______________?
A Headaches
B Itchy skin
C A violent explosion
D Nerve damage
121. The amount of superheat remains approximately constant to _____________?
A Keep the system in balance
B Prevent sludging of the compressor
C Prevent liquid from entering the discharge line
D Prevent liquid from entering the suction line
Copyri
ght
Rob Este
ll
122. Most motors are rated on the basis of __________?
A Horsepower
B Amperage
C Temperature rise when running fully loaded
D Voltage
123. Using R-22 vapor from the evaporator to the compressor at 40 F suction and 105 F condensing, with 300
feet of developed length, a 2 PSI drop, a 3 5/8 inch pipe should be capable of supporting how many tons?
A 43.2
B 52.5
C 87.5
D 63.0
124. The looping of hot gas from the compressor is usually done by a degree loop.
A 45
B 90
C 180
D 360
125. Using R-22 with 25 tons and a 1 5/8 inch line, the gas velocity in feet per minute is _____________?
A 4,000
B 6,000
C 1,000
D 2,000
126.The equivalent length in feet is 50. R-22 is being used from the evaporator to the compressor. The suction
is 35 degrees Fahrenheit and 115 degrees Fahrenheit condensing. The pressure drop is 2.0 psi. The minimum
tonnage using a 7/8 inch Type "L" copper line is __________?
A 3.4
B 3.8
C 3.52
D 38.08
127. Once the compressor is fully unloaded, any further system load reduction causes the _________?
A System to overheat and shut down
B Compressor suction pressure and temperature to fall accordingly
C THX valve to automatically close and open
D Oil pressure to decrease and the system to chug
Copyri
ght
Rob Este
ll
128. The suction line is from the _______________?
A Evaporator to the compressor
B Condenser to the evaporator
C Compressor to the condenser
D Compressor to the evaporator
129. Because of very short piping and little resistance to spray water flow, the ___________for an evaporative
condenser is considerably lower than that of a cooling tower system of equal capacity.
A Brake differential
B Enthalpy
C Pump horsepower
D Blowdown
130. Oil pressure failure controls operate using how many pressure sensitive lines?
A 1
B 2
C 3
D 4
131. The gage reading for R-12 at 40 degrees Fahrenheit is _________?
A 51.6
B 36.9
C 49.8
D 35.1
132. A proportional controller produces a control signal.
A Modulated
B Vibratory
C Differential
D Magnified Copyri
ght
Rob Este
ll
Answers
1 C 30
2 A 34
3 A 169
4 C 118
5 D 123
6 B 40
7 A 66
8 C 94
9 D 60
10 C 114
11 A 118
12 B 61
13 C 96
14 B 108
15 A 172
16 A 40
17 D 118
18 B 33
19 C 50
20 A 91
21 D 5
22 A 1
Copyri
ght
Rob Este
ll
23 C 4
24 D 95
25 B 91
26 A 131
27 D 95
28 B 93
29 D 91
30 B 97
31 A 131
32 B 59
33 A 55
34 C 56
35 B 71
36 C 92
37 D 106
38 D 128
39 B 121
40 D 167
41 D 4
42 B 4
43 A 4
44 B 4
45 A 124
231 + 227 + 233 + 3 = 230.3
231 - 230.3 = .66 230.3 - 227 = 3.33 233 - 230.3 = 2.66
.66 + 3.33 + 2.66 + 460.6% Yields 1.44
Copyri
ght
Rob Este
ll
46 C 4
47 D 130
48 C 3
49 C 92
60 + 2.7 + (2 X 3.2) + 102 + 2.2 = 173.3
50 B 49
51 B 56
52 D 61
53 B 71
54 D 106
55 D 108
56 A 128
57 D 130
58 B 3
59 B 3
60 A 4
61 D 4
62 D 124
226 + 230 + 241 + 3 = 232.3
(232.3 - 226) + (232.3 - 230) + (241 - 232.3)
6.3 + 2.3 + 8.7 = 17.3
17.3 + (2 X 232.3) % Yields 3.7
63 3
64 4
65 92
40 + 3 + (2 X 3.8) + 115 + 2.6 = 168.2
Copyri
ght
Rob Este
ll
66 A 5
67 B 106
68 B 4
69 A 55
70 A 1
71 D 53
72 C 59
73 B 118
74 A 19
75 B 77
76 B 133
77 A 76
78 A 91
79 B 17
80 B 76
81 B 118
82 A 3
83 C 4
84 D 66
85 A 124
230 + 225 + 232 ÷ 3 = 229
(230 - 229) + (230 - 229) + (232 - 229)
1 + 4 + 3 = 8
8 ÷ 458% is 1.746 = 1.75
86 131
87 93
Copyri
ght
Rob Este
ll
88 D 93
360 + 12 = 30'
89 B 14/91
90 B 92/93
91 B 3
92 D 4
93 C 52
94 C 61
95 A 3
96 B 4
97 D 52
98 C 53
99 B 54
100 B 4
101 C 61
102 A 92
103 C 93
104 D 118
105 B 124
106 A 167
107 A 3
108 C 3
109 B 4
110 D 52
111 A 53
112 A 73
Copyri
ght
Rob Este
ll
113 C 56
114 B 86
115 C 92
116 C 93
117 A 35
118 B 124
119 B 71
120 A 87
121 C 11
122 D 40
125 D 4
124 A 77
125 A 95
126 B 92/93
127 B 17
128 A 76
129 C 35
130 B 53
131 B 3
132 A 50 Cop
yrigh
t
Rob Este
ll