RMO REVIEW 3 Flashcards by Ivan Ng

Liquid level gauge glasses (except bull’s eye type) shall have shut off valves:

A. Manual only
B. Automatic only
C. Valves not needed
D. Manual and automatic

D. Manual and automatic

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Convert 20 psig to “HG Absolute

A. 30
B. 70
C. 80
D. 90

B. 70

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Why can’t you use a flare fitting ¾” or larger?

A. Can’t flare that large
B. Can’t tighten to get a good seal
C. Against the law
D. Easier to sweat

B. Can’t tighten to get a good seal

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For systems containing 50 lbs of refrigerant, stop valves are required:

A. At inlet of each compressor
B. At inlet of liquid receiver
C. Before and after sight glass
D. Not required

A. At inlet of each compressor

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The amount of ventilation for refrigerant removal purposes in a machine room shall be sized according to:

A. Total amount of refrigerants in unit
B. Total amount of the most flammable refrigerant
C. Total of the refrigerant in the largest machine
D. Total amount of refrigerant in units and stored in machine room

C. Total of the refrigerant in the largest machine

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The outlet from a fan or air duct used to ventilate refrigerants must be at least _____ feet from any air intake or exhaust or any opening in an adjoining building.

A. 5
B. 10
C. 20
D. 50

B. 10

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You are a RMO and you want to work on the machine’s pressure relief valve on a dual pressure relief valve system. What valve would you install to work on one pressure relief valve while allowing the other to operate in the system?

A. Gate valve
B. Butterfly valve or plug valve
C. Two-way valve
D. Three-way valve

D. Maintain a constant condenser pressure

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You are an RMO and you start the machine and the machine doesn’t start. Your fuses, circuit breakers and electrical components are all good. What would you check next?

A. Sight glass
B. Thermostat
C. Low pressure cut-out, pressure switch
D. Refrigerant charge

C. Low pressure cut-out, pressure switch

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What is superheated vapor?

A. Very high temperature gas mixed with fluid
B. Dry vapor
C. Dry vapor at its boiling point
D. Dry vapor above its boiling point

D. Dry vapor above its boiling point

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How does a solenoid valve work?

A. Open a plunger and allow refrigerant in
B. Open a spring valve and allow refrigerant in
C. Manually opens and allow refrigerant in
D. Manually closes and prevents refrigerant in

A. Open a plunger and allow refrigerant in

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A water regulating valve is connected to the outlet of the condenser. What is this valve designed to do?

A. Maintain a condenser pressure within pre-set limits
B. Maintain a constant water pressure
C. Maintain a constant water temperature
D. Maintain a constant condenser pressure

A. Maintain a condenser pressure within pre-set limits

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You are an RMO and you start the machine and the machine doesn’t start. Your fuses, circuit breakers and electrical components are all good. What would you check next?

A. Sight glass
B. Thermostat
C. Low pressure cut-out, pressure switch
D. Refrigerant charge

C. Low pressure cut-out, pressure switch

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12.	When a thermostatic expansion valve is operating properly, the end of the coil will contain:
A.	Saturated vapor
B.	Superheated vapor
C.	Low temperature liquid
D.	Hot vapor

B. Superheated vapor

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A compressor that uses a shaft with a mechanical seal. What is the valve plate made of?

A. Metal / carbon
B. Plastic
C. Rubber
D. Silicon

A. Metal / carbon

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On a valve plate, where are the suction and discharge valves located?

A. Suction on top, discharge on the bottom
B. Suction on bottom, discharge on top
C. Suction and discharge on top
D. Suction and discharge on bottom

B. Suction on bottom, discharge on top

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What controls a solenoid valve motor?

A. Watts
B. Volts
C. Horsepower
D. Amps

B. Volts

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Why is glycol a better brine than sodium chloride?

A. More conductive
B. Cost less
C. No corrosion
D. Higher freezing point

C. No corrosion

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What does a filter drier do?

A. Remove particles
B. Remove moisture
C. Remove acid
D. All of the above

D. All of the above

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How does a reciprocating compressor vary capacity?

A. Cylinder unloaders
B. Hot gas bypass
C. Motor speed variation
D. All of the above

A. Cylinder unloaders

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A safety head is a:

A. Pressure relief valve inside the compressor
B. Pressure relief valve on top of the head
C. Valve plate being held down with a spring
D. High side pressure in system below design pressure

C. Valve plate being held down with a spring

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When water turns to ice, what took place?

A. Superheat
B. Heat of fusion
C. Heat of evaporation
D. Sub-cooling

B. Heat of fusion

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Why do cascade systems use two compressors?

A. Split the cooling load
B. To accommodate high head pressure
C. To increase the compression ratio
D. To negate the effects of high compression ratio

A. Split the cooling load

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If the refrigeration oil is measured to have a viscosity and the viscosity number is low, what does that mean?

A. Doesn’t flow
B. Flows easily, smoothly
C. Flow is slow
D. Restricted flow

B. Flows easily, smoothly

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If you need to add another pump online, how do you do it?

A. Open the suction side valve and put the discharge valve in the throttle position
B. Open suction and close discharge
C. Close suction and open discharge
D. Open suction and slowly fully open discharge

A. Open the suction side valve and put the discharge valve in the throttle position

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24. The automatic expansion valve (AEV) is used instead of a TEV. It maintains a constant pressure on the evaporator. Another function it has is: A. Works well on variable loads B. Allows refrigerant on rise in pressure C. Needs temperature control to protect the evaporator from freezing up from cold water D. On water type evaporator, freezing will not occur

D. On water type evaporator, freezing will not occur

25. The pressure of water going through a shell and tube condenser is proportional to the square of its velocity. If it velocity originally was 40 and its original pressure was halved, what would be the velocity be? A. 40 B. 30 C. 20 D. 10

D. 10

26. If 10 BTU’s is transferred to 10 lbs of water, the increase in temperature is closest to: A. 10 F B. 10 C C. 1 F D. 1 C

C. 1 F

27. What is the order of components on the liquid line of a reciprocation system from the king valve? A. Filter drier, solenoid valve, sight glass, TEV to evaporator B. Solenoid valve, filter drier, sight glass, TEV to evaporator C. Sight glass, solenoid, sight glass, filter drier, TEV to evaporator D. TEV, sight glass, solenoid, filter drier to evaporator

A. Filter drier, solenoid valve, sight glass, TEV to evaporator

28. The unit used to measure the amount of electrons flowing past a certain point in an electrical circuit is called: ``` A. Ohm B. Ampere C. Volt D. Watt E. None of the above ```

B. Ampere

29. Before using a voltmeter, the technician should always: A. Zero the ohm adjustment B. Touch the two leads together to ensure continuity C. Set the range selector to a setting higher than the voltage expected D. Turn off the power E. None of the above

C. Set the range selector to a setting higher than the voltage expected

30. As an RMO you enter a system of a reciprocating refrigeration unit. This system has 150 lbs of refrigerant charge, you would expect to find stop valves: A. On the inlet supply and the discharge line B. Before and after the liquid bull’s eye sight glass C. On the inlet line of the condenser receiver D. On the inlet to each compressor

A. On the inlet supply and the discharge line

31. Regardless of the safety classification of the refrigerant in use, in the event 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

32. When you are finished leak testing with nitrogen and R-22, then the next step would be to: A. Vent refrigerant and nitrogen to the open air B. Remove refrigerant and nitrogen at the recovery machine C. Add refrigerant D. Add refrigerant if needed and put system back on line

A. Vent refrigerant and nitrogen to the open air

33. When oil leaves the sump in a centrifugal refrigeration system, where does the oil go? A. Travels with the refrigerant to cool the refrigeration system B. Travels back to the oil sump C. Is compatible with the refrigerant and will travel through the system and return to the oil sump D. Travels through the system and is drained out of the sump by a petcock valve

B. Travels back to the oil sump

34. The type of refrigerant in the feeler bulb on a system would be: A. The same as the refrigerant in the system B. Highly flammable / highly toxic C. Non-flammable / non toxic D. Would be a different type of refrigerant than the one in the system

C. Non-flammable / non toxic

35. What is the pressure of R-22 at 41 F? A. 38 psig B. 70 psig C. 18.5” Hg D. 81

B. 70 psig

36. Aside from venting refrigerant from your hose connection, the only other time you may discharge refrigerant would be: A. When a fire department engineer is present B. Never C. After the fire department engineer leaves the room D. To check if there is any refrigerant in the system

B. Never

37. After the compressor you have the oil separator, which: A. In general returns the oil to the crankcase B. Filters the oil and returns the oil to the crankcase C. Removes the water from the oil D. Distributes oil to the evaporator

A. In general returns the oil to the crankcase

38. An open type compressor is keeping the refrigerant from escaping by tightening a seal made of: A. rubber B. graphite loaded fiber C. carbon and metal D. fortified plastic

C. carbon and metal

39. How many BTU’s are absorbed by a 5 tons of ice? A. 188,000 B. 2,200,000 C. 1,440,000 D. None

C. 1,440,000

40. What are the recovery requirements for low pressure appliances? A. 25” Hg B. 0 psi C. 10” Hg D. 5” Hg

A. 25” Hg

41. If you are using a recovery machine to recover refrigerant from the system without using the system compressor, what kind of recovery machine is that? A. Self contained B. System dependent C. Centrifugal recovery machine D. None of the above

A. Self contained

42. When is a centrifugal water pump considered a “lift pump”? A. When the suction inlet of the water source is below the pump level B. When the discharge is 120 ft above C. When the water is lifted by the pump D. When the pump weighs less than 50 lbs

A. When the suction inlet of the water source is below the pump level

43. Where do non-condensables vapors and moisture collect? A. Liquid line B. Condenser C. Evaporator D. Filter drier

B. Condenser

44. After leak detecting with a mixture of nitrogen and a trace of R-22, the RMO: A. Has to recover only the R-22 B. Can vent the mixture to the atmosphere C. Recover both into the same container D. Recover both, but in separate cylinder

B. Can vent the mixture to the atmosphere

45. The RMO wants to get a temperature reading from the suction line but there are no gauges: A. The RMO can touch the line and use his experience to estimate what the temperature is B. Buy a thermometer and stick it to the suction line with putty C. Get two thermometers and get the average readings D. Touch the thermometer on the suction line and get a reading

B. Buy a thermometer and stick it to the suction line with putty

46. How do you control capacity of a centrifugal compressor with variable guide vanes? A. Increase sub-cooling B. Increase the speed of the motor C. Vary the passage of the vanes D. Piston valve clearance

C. Vary the passage of the vanes

47. A reciprocating compressor shaft seal is made up: A. Plastic B. Rubber C. Graphite fiber hemp D. Metal

D. Metal

48. What is the minimum height level inside the machinery room exhaust? A. Less than 5 feet B. More than 5 feet C. 25 feet D. 50 feet

A. Less than 5 feet

49. Centrifugal compressors use what kind of refrigerant? A. CFC’s B. High pressure refrigerants C. Low pressure refrigerants D. All of the above

D. All of the above

50. To prevent against structural collapse in pipe work, when installing bended copper tubing: A. Use annealed copper B. Use a spring bender C. Use a large radius D. Use a brazed elbows

C. Use a large radius

51. If the unloaders fails to operate when needed, what would happen? A. Evaporator pressure would remain unaffected B. Evaporator temperature goes down C. Compressor would short cycle D. Compressor would vibrate

B. Evaporator temperature goes down

52. AXV’s maintain constant evaporator pressure, they also: A. Close when the load increases B. Are used when there is a wide range in load C. Are affected by condenser head pressure D. Require other safety devices when being used in evaporators that chill water

A. Close when the load increases

53. On a centrifugal water pump the conditions are correctly primed when: A. It is full of water and all air has been purged out B. Water is leaking from the packing C. The packing will maintain the water in the pump D. No refrigerant leaking

A. It is full of water and all air has been purged out

54. A centrifugal pump operates at 92 feet head. What would the corresponding pressure in psig be the closest to? A. 180 B. 20 C. 40 D. 90

C. 40

55. An electrical wiring schematic would show: A. The path of electricity B. The diagram of a switch C. A point to point picture of all the wiring in the circuit D. Only DC wiring

A. The path of electricity

56. Refrigerant oil quality is measured in viscosity. The least desirable quality in the oil would be: A. High viscosity B. Sour taste C. Low viscosity D. None of the above

A. High viscosity

57. On the high side of the system, liquid stop valves should be placed: A. In front and after the bull’s eyesight glass B. On the suction line and discharge line after the compressor C. In front of and after the muffler D. All of the above

A. In front and after the bull’s eyesight glass

58. When reading the HP of a three-phase motor using a clamp on ammeter you would: A. Take measurement on all 3 phases B. Take a measurement on one phase only C. Ammeter reads only amp D. Take a voltage measurement

C. Ammeter reads only amp

59. If the chemical treatment would be temporarily unavailable, you would A. Weekly drain the tower and scrape clean everything B. Weekly change all the condenser water C. Change from city water to distilled water D. Change the bleeding setting of the tower water so more bleeding will take place

D. Change the bleeding setting of the tower water so more bleeding will take place

60. If you have 3 line cable supplying energy to your equipment and only two lines have fuses, the unfused line would be: A. Connect the extra line to make 3 phase B. 2 unfused wires do not need to be insulated C. The neutral line of a 120/240 circuit D. This would present an unsafe condition

C. The neutral line of a 120/240 circuit

61. What is the main disadvantage of the suction line filter drier compared to the liquid line filter drier? A. Suction line filter drier is harder to change than the liquid line filter drier B. Is less efficient than liquid line filter drier due to density of refrigerant C. Suction line filter drier is too big and bulky D. If it gets clogged, the suction line filter drier reduces more of the capacity of the compressor than the liquid line filter drier

D. If it gets clogged, the suction line filter drier reduces more of the capacity of the compressor than the liquid line filter drier

62. The electric power delivered to a liquid line solenoid valve is measured in: A. Ohms () B. voltage C. amps D. watts

D. watts

63. To raise 10 lbs of water 1 F, how many BTU’s do you need? A. 1 B. 5 C. 20 D. 10

D. 10

64. What is the total maximum amount of refrigerant you can store in the machinery room apart from your refrigerant in your machine? A. 100 lbs B. 150 lbs C. 300 lbs D. 5 drums

C. 300 lbs

65. 500 BTU’s are removed from 50 lbs of water at 60 F. What us the final water temperature? A. 40 F B. 50 F C. 70 F D. 60 F

B. 50 F

66. Ventilation in the machine room depends on the: A. Amount of flammable refrigerant B. Amount of refrigerant stored in the container C. Amount of refrigerant in the machine D. The total amount of refrigerant in the machine room

C. Amount of refrigerant in the machine

67. How do you increase the pressure of a centrifugal compressor? A. Variable guide vanes B. Increase sub-cool level C. Increase speed of the motor D. All of the above

C. Increase speed of the motor

68. After oil circulates in a centrifugal machine, where does the oil settle and how do you extract it out? A. Compressor crankcase and drain B. Oil sump and drain from oil valve C. Condenser bottom and liquid service valve D. Evaporator and extract from drain valve

B. Oil sump and drain from oil valve

69. What is the reason to put two low-side floats in parallel? A. You make a repair without interrupting the other B. Each one feeds its own evaporator C. If one clogs, flow will continue through the second D. When the load decreases it will feed faster

B. Each one feeds its own evaporator

70. A motor pulley has a diameter of 3” and runs at 1,400 rpms. The fan pulley has a diameter of 5 ¼” , at how many revolutions per minute does the fan pulley revolve? A. 800 rpms B. 1,600 rpms C. 200 rpms D. 1,800 rpms

A. 800 rpms

71. The center port of the gauge manifold is connected to the: A. Recovery machine B. Charging cylinder C. Vacuum pump D. All of the above

D. All of the above

72. The suction valve on a reciprocating machine is frontseated. You have evacuated down to 25” Hg. You shut the vacuum pump off and the low side pressure rises immediately. What is the cause? A. Faulty suction service valve B. Faulty (suction) compressor valve C. Faulty discharge valve D. Faulty liquid line stop valve

B. Faulty (suction) compressor valve

73. What is used to track speed of a steam turbine? A. Tachometer B. Speedometer C. pedometer D. trackometer

A. Tachometer

74. what is the steam jet on the surface condenser used for? A. To create high pressure to maintain high steam velocity B. To maintain steam level inside condenser C. To create proper exhaust vacuum D. All of the above

C. To create proper exhaust vacuum

75. How do you keep proper water level in the hot well? A. Slow turbine down B. Alternate speed of turbine C. Vary flow of condenser water D. With the overboard and recycling valve

D. With the overboard and recycling valve

76. How long does it take to warm up a steam turbine? A. 15 – 20 minutes B. 30 – 40 minutes C. No less than 60 minutes D. Doesn’t need to warm up

A. 15 – 20 minutes

77. What is the auxiliary oil pump used for? A. Starting-up B. Lubricating the main pump bearings C. Only used when main pump is malfunctioning D. Used in reciprocating machines

A. Starting-up

78. What would best describe the refrigerant in the last evaporator coil? A. Vapor B. Saturated vapor C. Superheated vapor D. Dry vapor

C. Superheated vapor

79. In addition to evaporator pressure, what other force determines the flow through an automatic expansion valve? A. Spring pressure B. Condenser pressure C. Cut-in pressure D. Design pressure

A. Spring pressure

80. You are using copper tubing to replace a part of the refrigeration system. What is used to bend the tubing? A. Pipe hickey B. Spring type tube bender C. Vise D. Pinch bar

B. Spring type tube bender

81. Which of the following best describes the need for using cascade systems? A. To increase the system’s compression ration B. To decrease the system’s compression ration C. To obtain low evaporator temperatures D. To produce ice

C. To obtain low evaporator temperatures

82. The strength of the strong liquor in an absorption system decreases as the: A. Expansion valve is opened B. Condenser pressure decreases C. Evaporator load increase D. Evaporator load decreases

D. Evaporator load decreases

83. In an Ammonia absorption system the analyzer is located between the: A. Generator and rectifier B. Absorber and evaporator C. Rectifier and condenser D. Condenser and receiver

A. Generator and rectifier

84. How is a wattmeter used? A. By using 4 leads and taking 1 reading B. By taking 3 readings C. By using the ohmmeter D. All of the above

A. By using 4 leads and taking 1 reading

85. The true power consumed by an induction motor can best be described by the following formula: A. Current x voltage x power factor B. Current x voltage C. Voltage x resistance D. Current x resistance

A. Current x voltage x power factor

86. What is the purpose of the gland steam? A. Create positive pressure B. Eliminate leakage at the end of the shaft C. To heat the gland D. Both A and B are correct

D. Both A and B are correct

87. The overspeed trip is: A. A device that will slow the machine down in the event of excessive speed B. A gimble safety valve to stop the turbine in the event in the event of the RPMs reaching over the maximum speed C. A device used to de-energize the motor starter to shut the motor down in the event the RPMs reaching over the maximum speed D. A mechanism used to signal the machine to increase speed

B. A gimble safety valve to stop the turbine in the event in the event of the RPMs reaching over the maximum speed

88. What are wearing rings used for? A. To prevent the wearing on the impeller or casing B. To decrease the tolerance between the impeller and casing C. To increase efficiency D. Any of the above

D. Any of the above

89. What type of bearing is used for turbine rotor shaft? A. Needle bearing B. Sleeve bearing C. Ball bearing D. Kingsbury bearing

D. Kingsbury bearing

90. Which of the following electrical components have the ability to store electricity and are sometimes used to start motors? A. Resistor B. Rectifier C. Generator D. Capacitor

D. Capacitor

91. Which is the best to use when soldering copper, iron or steel? A. Brazing alloys B. Any low temperature solder C. 50 – 50 tin lead D. Silver solder

D. Silver solder

92. Water when mixed with refrigerant in a reciprocating system will: A. Lubricate the system B. Form acids and sludge C. Cause non-condensables to form D. Freeze-up in the condenser

B. Form acids and sludge

93. What is a major advantage of having a two stage centrifugal compressor with impellers back to back? A. Lower thrust load on bearings B. One of the impellers can be stopped to adjust to the load conditions C. You can use different evaporators to feed different refrigerants to each D. They can also operate at a lower speed than the single stage

D. They can also operate at a lower speed than the single stage

94. A halide torch is to be used outside on a rooftop to check for leaks on a refrigeration unit. Why should you not generally use this device outside? A. Rain can get in and affect it performance B. Wind can affect the flame size C. You will not be able to detect the change in color due to the brightness outside D. Oxygen outside may cause an explosion

C. You will not be able to detect the change in color due to the brightness outside

95. The pump seal prevents water from leaking on a centrifugal water pump when under positive pressure. What other function may it have? A. Allows water to leak off when using mechanical seal type B. Shows that water is inside when it is dripping C. Prevents air from entering when it is under negative pressure D. Steam creates positive pressure to prevent steam leakage

C. Prevents air from entering when it is under negative pressure

96. A “lift pump”: A. Actually lifts water to the pump suction B. Is located above the section pipe feeding it C. Is a pump that is relative light in weight and can be lifted D. Is a safety pump used to protect the system

A. Actually lifts water to the pump suction

97. An operator has been assigned to run a centrifugal compressor. The capacity control is most likely achieved by: A. Increasing the speed of the impeller B. Adjusting the size of the vane passages C. Decreasing the speed of the impeller D. Solenoid unloaders

B. Adjusting the size of the vane passages

98. What information must be stamped on a fusible plug? A. Type of refrigerant that it can be used with B. Increases as the suction pressure increases C. Decreases as the discharge pressure increases D. Increases as the discharge pressure decreases

B. Increases as the suction pressure increases

99. 1,000 BTU’s of heat is added to 100 lbs of water. How many degrees did the temperature of the water increase? A. 10 C B. 10 F C. 1 C D. 1 F

B. 10 F

100. Quick-connect fittings are considered as: A. Low-loss fittings B. Soldered fittings C. Flare fittings D. Automatic loss fitting

A. Low-loss fittings

RMO REVIEW 3 Flashcards

(101 cards)