1
Q
- Of the following characteristics of refrigerant, the one that best describes R-22 is:
A. Odorless when mixed with air
B. An ether like odor when mixed with air
C. Explosive when mixed with air
D. Boils at a higher temp than R-12 at atmospheric pressure
A
A. Odorless when mixed with air
2
Q
- Because of the latent heat load, refrigeration machine operator was instructed to start the reciprocating plant for air-conditioning. Of the following according to recommended practice, the first thing to do is:
A. Turn on chilled water pumps and open the bypass to lighter load
B. Install larger fuse to take the initial load, and then turn on the cooling tower fans
C. Turn on chilled water pump, condenser water pumps and cooling tower fans
D. Set the thermostat a few degrees higher
A
C. Turn on chilled water pump, condenser water pumps and cooling tower fans
3
Q
- The most important reason to use 2 compressors in a cascade system is to:
1 Accomplish lower temperature
2 Permit the use of inexpensive lubricating oil
3 Avoid the need for very high compression ratios
4 Divide the cooling load between two compressors
A
Accomplish lower temperature
4
Q
- The advantage of forced draft over natural draft cooling tower is:
A. The possibility of lower water out temp
B. There is no dependence on natural wind velocity
C. Use a smaller tower size
D. All of the above
A
D. All of the above
5
Q
- What is 29.92” HG in KPA
A. 101.3
B. 101.28
C. 101.26
D. 103.2
A
A. 101.3
6
Q
- In this picture the mechanism sitting above the evaporator is known as:
A. Economizer
B. Purge unit
C. Air bleed
D. Pressure relief device
A
B. Purge unit
7
Q
- The rupture disk is always piped into the:
A. High side
B. Low side
C. Either side of the system
D. Neither side of the system
A
B. Low side
8
Q
- Concerning leakage, which state is most correct?
A. Gate valve causes less leakage
B. Globe valve causes more leakage
C. All valves are the same
D. Gate valve causes more leakage
A
D. Gate valve causes more leakage
9
Q
- What shaft seal prevents vapor from leaking out of the compressor?
A. Stuffing box
B. Electro-mechanical seal
C. Mechanical seal
D. All of the above
A
C. Mechanical seal
10
Q
- A fusible plug melts at:
A. 450 F
B. 280 F
C. 212 F
D. 800 F
A
B. 280 F
11
Q
- When will the BTUs absorbed by the condensing water be the greatest?
A. Low cond. Temp low cond. water temp
B. High cond. Temp, high cond. Water temp
C. High cond. Temp low cond. Water temp
D. Low cond. temp, high cond. Water temp
A
C. High cond. Temp low cond. Water temp
12
Q
- Flooded evaporators have high heat transfer per square foot, what may be a disadvantage?
A. Requires a smaller charge
B. Requires a larger charge
C. Requires the use of a TXV for proper feed
D. Water has to be drained daily
A
D. Water has to be drained daily
13
Q
Shell and tube condensers have the advantage of:
A. Removing heads for cleaning the water sides of the tubes
B. The refrigerant connections does not have to be disrupted
C. Using acid for clean
D. Both A and B
A
B. The refrigerant connections does not have to be disrupted
14
Q
- Shell and coil condensers have the advantage of:
A. Removing heads for cleaning the water sides of the tubes
B. The refrigerant connections does not have to be disrupted
C. Has less chance of developing leaks
D. Both A and B
A
B. The refrigerant connections does not have to be disrupted
15
Q
- How many BTUs would be removed in a 30-ton system?
A. 12,000 per hour
B. 360,000 per minute
C. 12,000 per minute
D. 360,000 per hour
A
D. 360,000 per hour
16
Q
- If you have 62 psi at 35 F and 70 PSI at 45 F what would 38 F be?
A. 66
B. 64.4
C. 65
D. 62
A
B. 64.4
17
Q
- Copper is used in refrigeration systems, like in heat exchangers, because?
A. Easy fabrication
B. East durability
C. High Thermal conductivity
D. Flexibility
A
B. East durability
18
Q
- The accessories on the liquid line are in what order?
A. Solenoid valve, drier and sight glass
B. Receiver, drier, solenoid valve and sight glass
C. Muffler, drier, sight glass, and solenoid valve
D. Accumulator, muffler, drier, sight glass
A
A. Solenoid valve, drier and sight glass
19
Q
- A condenser is 20’ long and 6’ diameter, what is the volume in gallons if 7.89 gallons is 1 cu/ft?
A. 565
B. 4227
C. 1808
D. 1205
A
D. 1205
20
Q
- What is this used for?
A. Recycling
B. Recovering
C. Reclaiming
D. Purging
A
B. Recovering
21
Q
- If the low pressure cutout cycles the compressor off, what starts the compressor again?
A. Solenoid valve
B. High pressure cut-out
C. Low pressure cut-out
D. Thermostat
A
D. Thermostat
22
Q
- Removing the insulation on the suction line, with the engine temperature at 85 F, what will occur?
A. Flooded evaporator
B. Starved evaporator
C. Excessive superheat
D. Low superheat
A
C. Excessive superheat
23
Q
- If you were running three compressors, which best describes the state of refrigerant leaving the third evaporator coil?
A. Mostly liquid, some vapor
B. Mostly vapor, some liquid
C. Superheated vapor
D. Highly superheated vapor
A
C. Superheated vapor
24
Q
- What type of pump is this?
A. Centrifugal chilled water pump
B. Reciprocating condenser water pump
C. Reciprocating chilled water pump
D. Centrifugal condenser water pump
A
A. Centrifugal chilled water pump
25
25. An electric motor that is rated at 3 HP will?
A. Use three phase
B. Need a capacitor
C. Use single phase
D. Will run with reduced power output
C. Use single phase
26
26. In a 3 stage centrifugal chiller, what happens to the pressure as it reaches the final stage?
A. Increases
B. Decreases
C. Speed changes not pressure
D. Volume changed not the pressure
A. Increases
27
27. With an induced draft cooling tower, what is the lowest temperature attainable for a cooling tower?
A. Wet bulb equal to dry bulb
B. Dry bulb slightly lower than wet bulb
C. Dry bulb higher than wet bulb
D. Wet bulb can never be lower than dry bulb
A. Wet bulb equal to dry bulb
28
28. When a compressor is running fine at full flow and you throttle down flow causing the compressor to stop running normal (short cycle), why would this happen?
A. Dirty filter/strainer
B. Air getting in seals
C. Low pressure cut out
D. High head pressure
C. Low pressure cut out
29
29. When dry bulb is 75 F and wet bulb is 75 F:
A. Not possible
B. Very low humidity
C. Thermometer is defective
D. 100% relative humidity
B. Very low humidity
30
30. When a compressor is said to have a safety heat this means:
A. Compressor operates with normal pressures
B. Compressor operates with low pressures
C. Compressor has pressure relief device
D. Compressor has high pressure cut-out
B. Compressor operates with low pressures
31
31. The cylinder unloader controls capacity, is there any other function it may have?
A. Assist with compressor shut down
B. Assist with compressor start up
C. There is no other function
D. Releases pressure for protection
C. There is no other function
32
32. An operator suspects that shorted motor windings have caused the motor overloads to trip. In order to investigate this condition, the operator would be most correct to use:
A. Capacitor
B. Voltmeter
C. Ohmmeter
D. Ammeter
B. Voltmeter
33
33. When recovering R-22, what color would the cylinder be that you are storing the refrigerant in?
A. Yellow tops
B. White tops
C. Green tops
D. Gray tops
B. White tops
34
34. If unloaders were to fail in the unloaded position, what happens in a system using reciprocating compressor?
A. The evaporator will starve
B. Cause high superheat
C. Not enough refrigerant to coil
D. All of the above
B. Cause high superheat
35
35. When the temperature and the load increase and you need to add another pump online, you would:
A. Close both suction and discharge
B. Open both suction and discharge
C. Open suction and throttle discharge
D. Open discharge bypass and close suction
A. Close both suction and discharge
36
36. When a system does not have unloaders, what is needed?
A. Other capacity control
B. Variable inlet guide vanes
C. An economizer
D. Solenoid on liquid line
A. Other capacity control
37
37. When an evaporator is not equipped with an equalizer line, you would most likely find:
A. Feeler bulb placed in different area
B. A distributor
C. An automatic expansion valve
D. Both high and low side pressures identical
D. Both high and low side pressures identical
38
38. When you plan on overhauling a system and you have recovered all liquid refrigerants, what is next?
A. Go ahead and do the work
B. Recover all the vapor, then do the work
C. Send liquid nitrogen through
D. Evacuate system
D. Evacuate system
39
39. When there is a 5 lbs pressure drop across evaporator, you need an external equalizer line, what happens if it disconnects?
A. Excessive superheat
B. Evaporator would starve
C. Evaporator would flood
D. TEV would not function
B. Evaporator would starve
40
40. The metering device used in a condenser is a high side float, this device will:
A. Control the amount of water in condenser
B. Control the amount of refrigerant in condenser
C. Keeps a constant pressure
D. Keeps a constant temperature
B. Control the amount of refrigerant in condenser
41
41. If a low side float is being used:
A. Pressure will be constant
B. It will control refrigerant flow
C. It will control water flow
D. Temperature is constant
D. Temperature is constant
42
42. The heat that boils off in a condenser is:
A. Latent heat
B. Sensible heat
C. Superheat
D. All of the above
B. Sensible heat
43
43. The condenser that uses air and water for cooling is the:
A. Air cooled
B. Water cooled
C. Evaporative
D. Both A and B are correct
C. Evaporative
44
44. A hermetic compressor is operating with a low refrigerant charge. What is the most likely effect this condition would have on the compressor?
A. Head pressure would rise
B. Compressor would operate at a higher temperature
C. Have no effect on the compressor
D. Oil pressure would rise
D. Oil pressure would rise
45
45. A refrigeration unit is measured in:
A. Watts
B. Volts
C. BTUs
D. Temperature
A. Watts
46
46. A centrifugal chiller has a suction pressure of 18” HG vacuum and discharge pressure of 6 psig. What is the compression ratio of this unit?
A. 3.50
B. 2.96
C. 1.75
D. 2.76
B. 2.96
47
47. What is a method used to calibrate a thermometer?
A. Place thermometer in cup of ice
B. Place thermometer in superheated stem
C. Lower temperature on thermometer
D. Raise temperature on thermometer
C. Lower temperature on thermometer
48
48. If you had to install a solenoid valve to a system which uses 110 volts and needed to convert it to 24 volts, what would you use?
A. Step up transformer
B. Step down transformer
C. AC to DC rectification
D. Rewire circuit with smaller gauge wire
A. Step up transformer
49
49. If you had 38 F in the evaporator, what should your suction pressure be for R-22?
A. 66 psia
B. 66 psig
C. 76 psig
D. 76 psia
C. 76 psig
50
50. An oil with low viscosity would:
A. Not be used for refrigeration
B. Be used for engine/motors
C. Be used for air conditioning
D. Both B and C are correct
A. Not be used for refrigeration
51
51. When charging a centrifugal system the position of the valve is
A. Front seated
B. Back seated
C. Cracked off the back seat
D. Closed
A. Front seated
52
52. The suction and discharge valves in a reciprocating compressor are positioned:
A. Over valve plate
B. Under valve plate
C. Both under and over valve plate
D. None of the above
B. Under valve plate
53
53. What refrigerants are you not able to dump?
A. CFC
B. HCFC
C. HFC
D. Any refrigerant containing chlorine or fluorine
C. HFC
54
54. There is an automatic water regulating valve on a reciprocating chiller. Water is entering the condenser at 85 F and leaving the condenser at 88 F you know there is no scale and the tubes are not covered with film. What can be causing this condition?
A. High head pressure
B. Low suction pressure
C. Water valve stuck open
D. Water valve stuck closed
A. High head pressure
55
55. How low can chiller water temperature be?
A. 32 F
B. 33F
C. 38 F
D. 42 F
C. 38 F
56
56. While using a halide torch to check for refrigerant leaks, if the flame was to turn yellow, what happened?
A. Container is empty
B. Restriction in tube
C. Refrigerant is leaking
D. Refrigerant has high moisture content
B. Restriction in tube
57
57. What is the cubic feet of a 20 foot long 6 foot wide vessel on the evaporator?
A. 120 cu ft
B. 565 cu ft
C. 4235 cu ft
D. 4710 cu ft
B. 565 cu ft
58
58. A water regulating valve is installed in a water cooled condenser. The operating force on this valve is respondent to:
A. High side pressure
B. Chilled water temperature
C. Circulating water pressure through the condenser
D. Manual operation
D. Manual operation
59
59. Regarding the pump below elements A, B, C, D, and E correspond to the following:
A. 90 reducing elbow, pump discharge, pump casing, pump suction, vibration reducer
B. 90 reducing elbow, pump suction, pump casing, pump discharge, check valve
C. 45 reducing elbow, pump suction, motor housing, pump discharge, check valves
D. Straight 90, pump casing, motor housing, reducing elbow, vibration eliminator
D. Straight 90, pump casing, motor housing, reducing elbow, vibration eliminator
60
60. Compound gauges can measure:
A. Above atmospheric
B. Below atmospheric
C. Temperature
D. All of the above
B. Below atmospheric
61
61. A low pressure refrigeration system has a pin hole in the evaporator. What is the most likely result?
A. High head pressure
B. Frost around leak area
C. High condenser water pressure
D. Low condenser pressure
B. Frost around leak area
62
62. What does the centrifugal compressor generate inside?
A. High pressure, low velocity
B. High volume, low pressure
C. Low velocity, low pressure
D. High velocity, high pressure
C. Low velocity, low pressure
63
63. Oil flashpoint temperature in the compressor should be:
A. Lower than the heat of compression
B. Higher than the heat of compression
C. Equal to the heat of compression
D. Equal to the heat absorbed
D. Equal to the heat absorbed
64
64. Compressor motors that operate inside the refrigerant atmosphere:
A. Must use materials compatible with the system refrigerants
B. Motors must be assembled in clean atmosphere and kept dry
C. Are not worked on in the field
D. All of the above
D. All of the above
65
65. In a centrifugal three stage compressor:
A. Pressure increases with each stage
B. Impellers are same size
C. Impellers increase with each stage
D. Both A and B are correct
C. Impellers increase with each stage
66
66. An operator suspects that a vertical check valve on a discharge of a centrifugal pump is defective; this is a condenser pump and one of the three pumps in parallel. If the suspicion is true and the check valve fails to seat when required, the pump and connecting piping will most likely be damaged when:
A. Lubricating the pump
B. After having bled air form the pump casing petcock
C. Starting up and additional pump
D. Shutting the pump down
A. Lubricating the pump
67
67. In relation to the suction pressure of a compress, the reading in the oil pressure gauge should read:
A. 15-30 psi lower
B. 60-90 psi higher
C. 15-30 psi higher
D. 30-60 psi lower
D. 30-60 psi lower
68
68. The following most accurate statement regarding compressor motors that run in a refrigerant atmosphere is that they:
A. May use internal rubber cushions
B. May be repaired on sire when they malfunction
C. Use materials tailored to the refrigerant
D. Use same materials as a pump in air
B. May be repaired on sire when they malfunction
69
69. The follow is an example of an “inline” refrigerant cleaning system which may be used with a centrifugal compressor containing R-123 refrigerant is:
A. Refrigerant recovery
B. Refrigerant disposal
C. Refrigerant reclaiming
D. Refrigerant recycling
B. Refrigerant disposal
70
70. The accessory pointed out by the arrow below is:
A. Pressure gauge and globe valve
B. Temp. gauge and globe valve
C. Pressure gauge and gate valve
D. Bull’s eye sight glass and gate valve
B. Temp. gauge and globe valve
71
71. Regarding fire safety ANSI/ASHRAE, which classification indicates the latest flammability and least toxicity?
A. A1
B. B2
C. A2
D. B1
A. A1
72
72. Bubbles in the sight glass are most likely caused by:
A. An overcharged system
B. Non-condensable gases
C. Light load on the plant
D. Partially plugged filter/drier
D. Partially plugged filter/drier
73
73. In addition to regulating the refrigerant flow according to the needs of the system, metering devices also serve to:
A. Increase compressor capacity
B. Hold system to a constant load
C. Restrict flow of refrigerant from the high side to low side
D. Shed load as load increases
B. Hold system to a constant load
74
74. Regardless of safety classification the refrigerant in use, in the even of refrigerant escape, the RMO should be aware of
A. A refrigerant fire
B. Refrigerant poisoning
C. Oxygen deprivation
D. Atmospheric superheating
C. Oxygen deprivation
75
75. The refrigeration unit which you have been assigned to is being taken out of service for major repairs. You have been assigned to withdraw refrigerant for storage in suitable containers. According to the NYC fire law handbook you must ensure that containers:
A. Are approved by the US department of Transportation
B. Are approved by the facilities manager
C. Do not weigh more than 200 lbs when filled
D. Do not exceed 55 gal in capacity
C. Do not weigh more than 200 lbs when filled
76
76. An operator confirms that a chiller water pump in a refrigerating system employing R-123 is cavitating, of the following, the most likely cause for this condition is:
A. Malfunctioning of the water makeup float valve
B. Too much time in between pump servicing
C. Operating at sustained high loads
D. Lowering the chilled water temperature
D. Lowering the chilled water temperature
77
77. A RMO is logging readings form a reciprocating compressor refrigerating unit. The crankcase and compressor discharge temp. have dropped significantly and suction line pressure is high. Of the following the one that may cause this set of conditions is:
A. Compressor cycling
B. An expansion valve which is closed too much
C. An expansion valve which is open to wide
D. Faulty compressor valves
C. An expansion valve which is open to wide
78
78. The ratio of actual pressure of water vapor in the atmosphere to the saturation pressure/temperature is called:
A. Absolute humidity
B. Humidity effect
C. Partial pressure
D. Relative humidity
A. Absolute humidity
79
79. The dividing line between the high and low sides of the refrigeration system is:
A. The connection between the compressor and condenser
B. Needle valve mechanism
C. Compressor outlet and the orifice of the metering device
D. Center plate of the refrigeration mechanism
B. Needle valve mechanism
80
80. An operator verifies that a condenser water pump is cavitating in a refrigeration system employing R-22 refrigerant. Of the following the most likely cause for this condition is:
A. Air leaks though the pump packing
B. Operating at sustained high loads
C. Faulty cooling tower water level controller
D. Too long a period between pump servicing
D. Too long a period between pump servicing
81
81. An operator notices that a centrifugal pimp operates satisfactorily when delivering at full discharge, but loses water flow if throttled. The operator would most accurately assume that this condition is due to:
A. Water hammer
B. Clogged strainer in pump inlet
C. Poor bearing lubrication
D. Air leaks in the pump
B. Clogged strainer in pump inlet
82
82. Assuming that a refrigeration plant uses a horizontal shell and tube condenser with the water in the tubes and the refrigerant in the shell. In controlling the operation of the condenser, the operator should take into account that most likely the heat transfer rate BTU/per sq foot per second in the condenser will:
A. Show the least benefit for descaling tubes at high water velocities
B. Increase with the velocity of the water in the tubes
C. Increase the lower log mean temperature difference
D. Show only a small increase if the tubes are descaled
C. Increase the lower log mean temperature difference
83
83. Electric devices may be used to provide built in defrosting of refrigerating machine evaporator units. These devices are classified as:
A. Relays
B. Induction coils
C. Capacitors
D. Resistors
C. Capacitors
84
84. Latent heat and refrigeration effect are usually listed as refrigerant properties. The refrigerating effect is also always a lower value than the latent heat because the:
A. Heat required to cool the refrigerant from compressor discharge to evaporative temperature is subtracted from latent heat
B. Refrigerant latent heat is divided by specific gravity of the refrigerant
C. Refrigerant critical temperature is factored into the calculation of the refrigerating effect
D. Refrigerant latent heat is divided by the refrigerant circulation rate
C. Refrigerant critical temperature is factored into the calculation of the refrigerating effect
85
85. Superheated vapor flowing into a reciprocating compressor protects the compressor parts against liquid intake of the following, one of the problems associated with superheat is that:
A. Non-condensable are more prone to collect in the system
B. Frost may develop in the suction line
C. It will decrease the capacity of the compressor and the refrigeration machine
D. The compressor head pressure drops to low
B. Frost may develop in the suction line
86
86. An operator observes a reading of 60 C on a refrigerating unit. The same reading is Fahrenheit scale would be closer to:
A. 140 F
B. 185 F
C. 155 F
D. 170 F
B. 185 F
87
87. What is the state of refrigerant as it leaves the compressor and as it leaves the condenser:
A. Superheated vapor and superheat liquid
B. Superheated vapor and warm sub-cooled liquid
C. Saturated vapor and cold sub-cooled liquid
D. Saturated vapor and warm sub-cooled liquid
D. Saturated vapor and warm sub-cooled liquid
88
88. Clearance volume:
A. Affects compressor capacity
B. Is the space that traps liquid refrigerant
C. Varies, depending on compressor speed
D. Is the same on all compressors
C. Varies, depending on compressor speed
89
89. A thermal bulb is attached to the suction pipe between the evaporator coil and the compressor covered by an insulating line. Assuming the machine room is 85 deg F, unraveling of the insulation would result in:
A. Adequate superheat
B. Starved evaporator
C. Excessive superheat
D. Flooded evaporator
A. Adequate superheat
90
90. Of the following one of the primary reasons for the insulation of a crankcase breather line is:
A. Increase the compressor efficiency
B. To prevent oil slugging in the compressor
C. Keep the shaft packing lubricated
D. To prevent refrigerant from entering the compressor suction
D. To prevent refrigerant from entering the compressor suction
91
91. A RMO notices excessive cycling of the temperature control for a reciprocating compressor refrigeration unit. The crankcase temp is high and the suction line is high, of the following the one that may be causing this set of conditions is:
A. Purge unit operation
B. An expansion valve that is open too wide
C. Faulty compressor valves
D. Condenser operation, dirty tubes, or cooling water control
C. Faulty compressor valves
92
92. According to the NYC fire code classification of refrigerants, ammonia and sulfur dioxide are grouped into:
A. Group 2
B. Group 4
C. Group 1
D. Group 3
B. Group 4
93
93. A reciprocating system using an evaporative condenser, the muffler is installed between the:
A. Evaporator and compressor
B. Receiver and expansion valve
C. Compressor and evaporative condenser
D. Receiver and condenser
B. Receiver and expansion valve
94
94. While operating an R-12 reciprocating system, the RMO noticed the oil foaming in the crankcase, this condition most likely would have been caused by:
A. Addition of liquid Freon
B. Sudden drop in oil temperature
C. Sudden drop in crankcase pressure
D. Addition of oil to the crankcase
C. Sudden drop in crankcase pressure
95
95. Assume that a new valve plate has been installed while they are repairing a reciprocating compressor in a refrigeration plant. The installation of a new valve plate will require the replacement of:
A. All valve plates, springs and some valve seats
B. All valve and valve seats
C. Valve seats only
D. Suction valves only
D. Suction valves only
96
96. During a hot weekend, an RMO is instructed to start and additional reciprocating machine. The sequence of actions on start up would most likely be:
A. Check compressor oil, start cooling tower fans, check valves are in correct position, turn on machine, start chiller and condenser water pumps
B. Start chiller and condenser water pumps, start cooling water tower fans, check compressor oil levels, check that the valves are in correct position, turn on machine
C. Turn machine on, check valves are in correct position, start tower fans, check compressor oil levels, start chiller and condenser water pumps
D. Check valves are in correct position, start cooling water tower fans, start machine, start chiller and condenser water pumps, check compressor oil levels
A. Check compressor oil, start cooling tower fans, check valves are in correct position, turn on machine, start chiller and condenser water pumps
97
97. While doing a routine inspection, the RMO noticed the bulb of the TEV on the floor, the operator should attach the bulb at
A. Center of the coil
B. Expansion valve outlet
C. End of coil
D. ¾ away towards the end of the coil
A. Center of the coil
98
98. When operating a reciprocating refrigeration system with a belt driven compressor, an RMO notices that on of the 4 belts is broken. Of the following, the most advisable course of action for the RMO would be to:
A. Put more grease on the remaining belts
B. Replace all 4 belts with a new set
C. Replace the broken belt only
D. Operate with the remaining 3 belts
C. Replace the broken belt only
99
99. An operator reads the valve tag on a pressure relief valve and notices that the valve is set to unseat at an evaporator pressure of 15 psi, the corresponding set pressure in inches of HG is
A. 18
B. 14
C. 20
D. 30.3
B. 14
100
100. What is the maximum percentage that a refrigerant can be stored in a cylinder?
A. 75%
B. 80%
C. 90%
D. 100%
B. 80%
RMO REVIEW 1
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