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Comprehensive Review 5th Class Power Engineering > Book 2 Review > Flashcards

Book 2 Review Flashcards

1
Q

An electric starter motor on an internal combustion engine is usually supplied with ________ volt DC power.
A) 110
B) 32
C) 12
D) 6
E) 24

A

C) 12

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2
Q

One of the mechanical ventilation systems is the:
A) Natural air intake, mechanical exhaust
B) Forced air intake, natural exhaust
C) Forced air intake, mechanical exhaust
D) Forced air intake, forced exhaust
E) Natural air intake, forced exhaust

A

A) Natural air intake, mechanical exhaust

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3
Q

One of the advantages of a forced warm air heating system is:
A) The air can not be humidified
B) A more uniform temperature distribution can be obtained
C) The furnace must be located on the same floor
D) The air can not be cleaned by filters
E) The ducts can not be enclosed within walls and ceilings

A

B) A more uniform temperature distribution can be obtained

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4
Q

The condition known as “standard condition” indicates a standard evaporator temperature of:
A) 30ºC (86ºF)
B) -30ºC (-22ºF)
C) -15ºC (5ºF)
D) 15ºC (59ºF)
E) -10ºC (14ºF)

A

C) -15ºC (5ºF)

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5
Q

Which of the following is not a starting method for IC Gen-sets?
A) Electric
B) Compressed air starting motor
C) Manual crank
D) Compressed air to cylinder starting

A

C) Manual crank

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6
Q

An outdoor thermostat should be incorporated in the control system to protect the snow melting system from accidental operation during warm weather, by turning the system off when outdoor ambient temperature rises above:
A) 15ºC (59ºF)
B) 5ºC (41ºF)
C) 10ºC (50ºF)
D) 0ºC (32ºF)
E) 2ºC (35.6ºF)

A

E) 2ºC (35.6ºF)

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7
Q

The solenoid valve is operated by a/an _________ signal.
A) Electronic
B) Humidity
C) Electrical
D) Pressure
E) Temperature

A

C) Electrical

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8
Q

The activated carbon in an odour adsorber may be reactivated by heating it to __________ to drive out the adsorbed gases.
A) 500ºC (930ºF)
B) 250ºC (480ºF)
C) 175ºC (350ºF)
D) 538ºC (1000ºF)
E) 425ºC (800ºF)

A

D) 538ºC (1000ºF)

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9
Q

Weeping tile is usually installed to prevent an accumulation of ground water around the building foundations and to reduce _____________ water pressure on the walls below ground level.
A) Hydraulic
B) Hydronic
C) Hydrostatic
D) Hydroscopic
E) Hypostatic

A

C) Hydrostatic

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10
Q

To avoid cavitation in the pump and drawing air into the system, a positive pressure at the highest point of the system should be maintained of at least:
A) 76 kPa (11 psi)
B) 52 kPa (7.5 psi)
C) 12 kPa (1.7 psi)
D) 100 kPa (14.5 psi)
E) 20 kPa (2.9 psi)

A

C) 12 kPa (1.7 psi)

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11
Q

The purging unit of the refrigeration system should be operated for at least _________ minutes before the compressor is started (time depends on the size of the system)
A) 15
B) 5
C) 10
D) 25
E) 20

A

C) 10

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12
Q

In the two-pipe reverse return hot water heating system, the heating units are:
A) Equipped with its own circulating pump
B) All supplied with water at the same temperature and the return from each convector flows the long way around to return to the boiler
C) Supplied from the main and the return from each convector is connected back to the main again downstream from the supply connection
D) All supplied with water at the same temperature and the return from each convector flows by the shortest and most direct route back to the boiler
E) Connected in series so the water circulates from the hot water supply main directly through all the convectors to the return main

A

B) All supplied with water at the same temperature and the return from each convector flows the long way around to return to the boiler

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13
Q

Relative humidity is the amount of ___________ expressed as a percentage.
A) Moisture contained in the air compared to the minimum amount of moisture the air is capable of holding at the stated temperature
B) Moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at the stated temperature
C) Air contained in the moisture compared to the minimum amount of moisture the air is capable of holding at the stated temperature
D) Moisture contained in the air compared to the maximum amount of moisture the air capable of holding at any temperature
E) Air contained in the moisture compared to the maximum amount of moisture the air is capable of holding at the stated temperature

A

B) Moisture contained in the air compared to the maximum amount of moisture the air is capable of holding at the stated temperature

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14
Q

Building heat losses can be reduced to a large extent by adding a layer, or layers, of:
A) Building wrap
B) Insulation
C) Paint
D) Wall paper
E) Glass

A

B) Insulation

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15
Q

The material used for indoor sanitary drainage piping in single family dwellings is:
A) ABS plastic
B) PVC plastic
C) Cast iron
D) Galvanized steel
E) Copper

A

A) ABS plastic

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16
Q

A pilot type of air compressor unloader may operate in all except one of the following ways:
A) It may open a by-pass valve in the discharge back to the compressor intake
B) It may close the compressor intake line if compressor is a dynamic type
C) It may open a bleed vale to atmosphere and simply dump to atmosphere is the compressor is a large dynamic type
D) It may hold the cylinder inlet valves open if the compressor is reciprocating type
E) It may open a by-pass valve in the intake back to the compressor discharge

A

E) It may open a by-pass valve in the intake back to the compressor discharge

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17
Q

It is the _________ part of the refrigerant molecular composition that during combustion causes the green flame of the halide detector.
A) Hydrogen
B) Carbon
C) Fluorine
D) Iodine
E) Chlorine

A

E) Chlorine

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18
Q

An air receiver is a pressure vessel their specifications must conform to the:
A) ASME Code, Section VI
B) ASME Code, Section III
C) ASME Code, Section VIII
D) ASME Code, Section I
E) ASME Code, Section IV

A

C) ASME Code, Section VIII

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19
Q

The circulator in smaller systems normally produces only a slight pressure differential and, even when it is placed in the return line, a pressure of __________ will ensure that sufficient positive pressure is maintained at the highest points in the system.
A) 25 kPa(4 psi)
B) 10 kPa (1.5 psi)
C) 83 kPa (12 psi)
D) 55 kPa (8 psi)
E) 100 kPa (15 psi)

A

C) 83 kPa (12 psi)

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20
Q

Wetted litmus paper detects leaks in ammonia refrigeration systems by changing the colour of the litmus paper to a:
A) Orange
B) Reddish hue
C) Light blue
D) White
E) Bright green

A

B) Reddish hue

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21
Q

If the moving surfaces of materials can be separated from each other by a/an ________ so that their high spots do not come in contact with each other wear will be reduced or eliminated.
A) Grease
B) Oil
C) Lubricant
D) Solid
E) Space

A

C) Lubricant

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22
Q

An example of a dynamic compressor is the __________ compressor.
A) Rotary screw
B) Reciprocating
C) Sliding vane
D) Centrifugal
E) Rotary lobe

A

D) Centrifugal

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23
Q

If compressed air is used to start an IC gen-set, the _____________ is a critical issue.
A) Shaft temperature
B) The battery voltage
C) Speed of rotation
D) Cylinder pressure

A

D) Cylinder pressure

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24
Q

The gravity hot water heating system had a disadvantage of:
A) Simple operation and low maintenance
B) Positive circulation to radiators on the same level as the boiler
C) Small pipe sizes to keep flow resistance to a minimum
D) There is a slow response to changes in heat demand
E) The minimum water temperature is limited to 77ºC (171ºF)

A

D) There is a slow response to changes in heat demand

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25
Q

The main advantage of foil bearings in microturbines is:
A) The anti-wear coating
B) The high speed of shaft rotation
C) The use of an external pressurization system
D) The elimination of oil systems
E) The noise reduction

A

D) The elimination of oil systems

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26
Q

The pressure in the building plumbing system should not drop below _________ at any location.
A) 175 kPa (25 psi)
B) 250 kPa (36 psi)
C) 200 kPa (29 psi)
D) 150 kPa (22 psi)
E) 300 kPa (44 psi)

A

A) 175 kPa (25 psi)

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27
Q

Refrigerants that are highly flammable and highly toxic belong to Group:
A) A3
B) A2
C) B3
D) B1
E) B2

A

C) B3

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28
Q

The control of light produced by the lamp and is accomplished by the use of transparent, ___________, or opaque surfaces that refract, reflect, or absorb light directing it to the zones where it is required and preventing it from reaching the zones where it is not required.
A) Transcendental
B) Translucent
C) Transylvania
D) Transportation
E) Transamerica

A

B) Translucent

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29
Q

The material used for indoor sanitary drainage piping in commercial buildings is:
A) Cast iron
B) ABS plastic
C) Galvanized steel
D) PVC plastic
E) Copper

A

A) Cast iron

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30
Q

Temperatures are very important, and sometimes the cooling system includes a __________ which has pressures associated with it.
A) Water cooled
B) Cooling tower
C) Circulating pump
D) Temperature gauge
E) Air cooler

A

C) Circulating pump

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31
Q

One of the basic designs of water-cooled condensers is the _________ condenser:
A) Evaporative
B) Bare tube
C) Double tube
D) Direct expansion
E) Flooded

A

C) Double tube

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32
Q

A unit heater is a convector heater that employs __________ to force the air across the heating coil.
A) Differential pressure
B) Natural convection
C) A blower or fan
D) A pump
E) A turbocharger

A

C) A blower or fan

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33
Q

If the boiler water temperature was too low and the burner found to be out a probable cause would not be:
A) Low air switch activated
B) Flame failure device activated
C) Fuel valve not open
D) Low water cut off activated
E) Operating control set to low

A

E) Operating control set to low

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34
Q

The function of the refrigeration condenser is to cool the superheated refrigerant vapour until it _________ and then becomes sub-cooled.
A) Condenses to a liquid
B) Evaporates to a vapour
C) Evaporates to a liquid
D) Condenses to a vapour
E) Freezes

A

A) Condenses to a liquid

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35
Q

An air gap is a physical separation I between the free flowing discharge end of a portable water pipe and an open or non-pressure receiving vessel such as a:
A) Sink or a bathtub
B) Storage tank
C) Process vessel
D) Boiler
E) Mixing vat

A

A) Sink or a bathtub

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36
Q

External lubrication of the compressor refers to lubrication of all of the following except the:
A) Connecting rod bearings
B) Cylinder walls
C) Rotor shaft bearings on rotary and dynamic compressors
D) Crossheads on reciprocating compressors
E) Crankshaft bearings

A

B) Cylinder walls

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37
Q

The advantage of an all mechanical ventilation system is that the system supplies a controlled amount of __________ air and distributes it in such a way that any discomfort to the occupants is avoided.
A) Filtered and humidified
B) Filtered and cooled
C) Heated and humidified
D) Filtered and heated
E) Cooled and dehumidified

A

D) Filtered and heated

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38
Q

A cooling tower is a device that uses a combination of heat and mass transfer to lower the temperature of the:
A) Chilled water
B) Cooling water
C) Condensate
D) Refrigerant
E) Condenser

A

B) Cooling water

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39
Q

One of the three distinct classes of refrigeration controls is the ________ control.
A) Pressure actuated
B) Humidity actuated
C) Solenoid
D) Temperature actuated
E) Actuating or secondary

A

E) Actuating or secondary

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40
Q

In hydroid systems the expansion tank is a general term used to describe a piece of equipment for _________ in when heated.
A) Air to expand
B) Steam to accumulate
C) Water to expand
D) Water to cool
E) Water to heat

A

C) Water to expand

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41
Q

The high motor temperature cutout stops the compressor if there is a loss of motor cooling or a motor overload due to malfunction of the:
A) High oil temperature cutout
B) Condenser cooling water regulating valve
C) High-pressure safety cutout
D) Operating controls
E) Low limit thermostat

A

D) Operating controls

42
Q

The applicable code requires that each refrigerating system containing __________ or more of Group A1 refrigerant having an operating pressure over 103 kPa shall be constructed so that the refrigerant can be discharged into the atmosphere by means of a manually operated valve to be used in case of emergency.
A) 273.0 kg (600 lb)
B) 45.0 kg (100 lb)
C) 136 kg (300 lb)
D) 182.0 kg (400 lb)
E) 91.0 kg (200 lb)

A

D) 182 kg (400 lb)

43
Q

Which one of the following factors affect the leakage tendency of a refrigerant?
A) Molecule mass
B) Temperature
C) Miscibility
D) Enthalpy
E) Specific volume

A

A) Molecular mass

44
Q

One of the advantages of using a heat exchanger in a compression refrigeration system is:
A) Increasing the temperature of the vapour from the evaporator helps to prevent liquid slugging in the compressor
B) Decreasing the temperature of the vapour from the evaporator helps liquid slugging in the compressor
C) Increasing the temperature of the vapour from the evaporator helps to prevent liquid slugging in the evaporator
D) Decreasing the temperature of the vapour from the evaporator helps to prevent liquid slugging in the compressor
E) Increasing the temperature of the vapour from the evaporator helps liquid slugging in the compressor

A

C) Increasing temperature of the vapour from the evaporator helps to prevent liquid slugging in the compressor

45
Q

Refrigerants are classified in the Canadian Standards Association B52-05 Mechanical Refrigeration Code by their toxicity and flammability into the following ________ groups.
A) Six
B) Two
C) Four
D) Three
E) Five

A

A) Six

46
Q

In a typical electric control system in a warm air heating system the thermostat is referred to as the:
A) Controlled variable
B) Manipulated variable
C) Controller
D) Final control element
E) Set point

A

C) Controller

47
Q

The water to be cooled is distributed in the tower by spray nozzles and splash bars to expose a very __________ surface area to atmospheric air thus aiding evaporation.
A) Small water
B) Large air
C) Large water
D) Wet water
E) Small air

A

C) Large water

48
Q

The coefficient of performance is the ratio of the amount of heat absorbed from the refrigerated medium by the __________ to the amount of _____________.
A) Evaporator, energy used to drive the compressor
B) Condenser, energy used to drive the compressor
C) Compressor, energy used to drive the evaporator
D) Evaporator, energy used to drive the compressor
E) Condenser, energy released in the evaporator

A

A) Evaporator, energy used to drive the compressor

49
Q

One of the causes of insufficient steam supply to the heating units can be attributed to:
A) Bypassing of steam to return line
B) Air vents passing air
C) Valves on mains wide open
D) Piping over sized restricting flow
E) Proper pitch unrestricted drainage

A

A) Bypassing of steam to return line

50
Q

Lubricants in general may provide all of the following services except:
A) Minimum coefficient of friction
B) Minimum adhesion to the surfaces to be lubricated
C) Resistance to oxidation
D) Resistance to emulsion
E) Physical stability under variations of temperature and pressure

A

B) Minimum adhesion to the surfaces to be lubricated

51
Q

The operation of the compressor (starting, stopping, and unloading) may be accomplished by a _________ type of actuated control.
A) Mass
B) Density
C) Pressure
D) Volume Humidity
E) Level

A

C) Pressure

52
Q

The loss of heat from a substance will cause its temperature to drop, the heat removed from the substance is:
A) Latent heat
B) Sensible heat
C) Enthalpy heat
D) Sensible heat
E) Latent temperature

A

D) Sensible heat

53
Q

Which of the following statements about rotating mechanical seals is false?
A) The spring is fastened to the pump shaft
B) The mating ring is held stationary within the pump casing
C) The sealing ring will turn with the shaft
D) The mating ring will turn with the shaft
E) The sealing ring is fastened to the pump shaft

A

D) The mating ring will turn with the shaft

54
Q

Boiler checks are unnecessary in the automatic microturbine combined heating system.
A) True
B) False

A

B) False

55
Q

The benefits of a good preventative maintenance program may included all of the following except:
A) Control of labour and material cost
B) Reduced life expectancy of plant and equipment
C) Reduced spare parts inventory required
D) Accumulation of history records for each piece of equipment
E) Better means of identifying causes of breakdowns

A

B) Reduced life expectancy of plant and equipment

56
Q

One development in high efficiency warm air furnaces is the pulse combustion condensing furnace where the gases give up more heat and cool down to:
A) 100ºC (212ºF)
B) 150ºC (300ºF)
C) 38ºC (100ºF)
D) 50ºC (122ºF)
E) 65ºC (150ºF)

A

C) 38ºC (100ºF)

57
Q

One of the advantages of introducing a controlled amount of ventilation air into a building is:
A) The positive pressure will cause an outward escape of air through cracks, windows, and doors, and increase infiltration
B) The air will not have to be heated in winter
C) The air will not have to be cooled in summer
D) The ventilation air is introduced through the air conditioning equipment maintain a negative pressure within the building
E) Ventilation air can be reducing the labour and expense involved in cleaning and redecorating

A

E) Ventilation air can be reducing the labour and expense involved in cleaning and redecorating

58
Q

The male (driving) rotor in the helical screw compressor usually has ________ helical lobes along the length of the rotor.
A) Two
B) Four
C) Three
D) Five
E) Six

A

B) Four

59
Q

Thermal transmission or rate of heat flow is the:
A) Quantity of heat flow from all mechanisms, in unit time, under the conditions prevailing at that time (Q or W)
B) Reciprocal of thermal conductance, it is the value of a given material’s ability to resist heat transfer or flow (m2ºC/W)(ft2ºF/Btu/hr)
C) Thermal heat flow through a unit area of a non-uniform, composite material when a unit average temperature difference is established between the surfaces (W/m2ºC)(Btu/hr/ºF)
D) Thermal heat flow (transmission) through unit areas of a wall, door, window, etc for every degree temperature difference between the air/fluid inside and the air/fluid outside. (W/m2K or W/m2ºC)(Btu/hr/ftºF)
E) Thermal heat flow, by conduction only, through a unit area of a single uniform type material

A

A) Quantity of heat flow from all mechanisms, in unit time, under the conditions prevailing at that time (Q or W)

60
Q

Refrigerants that are non-toxic and non-flammable belong to Group:
A) B1
B) B2
C) A2
D) A3
E) A1

A

E) A1

61
Q

The compression ratio is calculated by dividing the:
A) Discharge gauge pressure by the Suction gauge pressure
B) Absolute suction pressure by the absolute discharge pressure
C) Discharge gauge pressure by the absolute suction pressure
D) Absolute discharge pressure by the absolute suction pressure
E) Absolute discharge pressure by the suction gauge pressure

A

D) Absolute discharge pressure by the absolute suction pressure

62
Q

The oil separator in a compression refrigeration system is placed between the:
A) Compressor and the condenser
B) Compressor and the evaporator
C) Condenser and the receiver
D) Expansion valve and the evaporator
E) Receiver and the expansion valve

A

A) Compressor and the condenser

63
Q

The carbon residue test is used to determine the amount of carbon which oil will form when subjected to:
A) High viscosity
B) High temperature
C) Low pressures
D) Low temperatures
E) High pressures

A

B) High temperatures

64
Q

What is the purpose of the chilled water flow switch?
A) Starts the chilled water booster pump
B) Starts the compressor on a low refrigerant flow condition
C) Opens the vanes so that the compressor can be restarted under load
D) It confirms refrigerant flow to the evaporator
E) Protects the chiller from freezing due to lack of water flow

A

E) Protects the chiller from freezing due to lack of water flow

65
Q

One of the wetted element humidifiers group is the ________ type.
A) Wet
B) Steam
C) Pan
D) Power
E) Spray

A

D) Power

66
Q

An example of a unitary air conditioning system could be all of the following except a:
A) Rooftop unit
B) Packaged air conditioner
C) Window air conditioner
D) Unit ventilator
E) Terminal reheater

A

E) Terminal reheater

67
Q

What must be provided when using a halide leak detector or when soldering or brazing on a refrigeration system?
A) Cool refrigerant temperatures
B) Sufficient flow from the leak source
C) Sufficient detectable odour from the refrigerant
D) A Class ABC fire extinguisher
E) Adequate ventilation

A

E) Adequate ventilation

68
Q

The __________ outlets should be located to prevent cold drafts from walls and windows and to maintain even temperature in the rooms.
A) Supply
B) Return
C) Grille
D) Plenum
E) Register

A

A) Supply

69
Q

Ordinarily, the most economical group relamping period is about ________ of rated life of the lamp.
A) 70%
B) 90%
C) 60%
D) 50%
E) 100%

A

A) 70%

70
Q

New building codes require to ensure proper ventilation with a heating furnace a fresh air duct be connected to the ________ side of the furnace.
A) Blower
B) Return
C) Filter
D) Plenum
E) Supply

A

B) Return

71
Q

When the pump is located above the source of supply and a separate hand-operated priming pump is used the pump is primed in the following manner except:
A) Close the priming valve
B) The priming pump valve is shut and the main pump is primed
C) Close the discharge valve
D) The pump is operated exhausting air from the main pump casing and suction line
E) Water issues from the priming pump discharge

A

A) Close the priming valve

72
Q

One type of electrical resistance heating element is the:
A) Encased tube
B) Encased wire
C) Open band
D) Open tube
E) Open ribbon

A

E) Open ribbon

73
Q

The additional heat added by the compressor results in the condenser being __________ larger in capacity than the evaporator.
A) 15% to 20%
B) 20% to 25%
C) 5% to 10%
D) 10% to 15%
E) 25% to 30%

A

A) 15% to 20%

74
Q

Most refrigeration systems are controlled by a motor demand limiter that limits the:
A) Minimum refrigerant flow to the evaporator
B) Maximum refrigerant flow to the compressor
C) Maximum water flow to the condenser
D) Minimum current flow to the compressor motor
E) Maximum current flow to the compressor motor

A

E) Maximum current flow to the compressor motor

75
Q

Air in hot water heating systems collects in the _______ of piping and heating units.
A) Return lines
B) Horizontal mains
C) High spots
D) Vertical risers
E) Down comers

A

C) High spots

76
Q

Most gas burners used in warm air furnaces are ________ burners.
A) Atmospheric
B) High-pressure
C) Spud
D) Ring
E) Pressurized

A

A) Atmospheric

77
Q

Usually the cause of the bearing trouble is one of the following:
A) Proper bearing design
B) Temperature of oil too high
C) True alignment of shaft and bearing
D) Excessive oil supply
E) Proper viscosity of oil

A

B) Temperature of oil too high

78
Q

___________ high-level lighting is provide for a work area or display without consideration of overall uniform ambient lighting.
A) Task
B) Combined
C) Non-uniform
D) Local
E) Uniform

A

D) Local

79
Q

An air washer is installed on the suction side of the fan so as to:
A) Add sensible heat to the air
B) Add moisture to the air
C) Add latent heat to the air
D) Avoid leakage of water through the joints
E) Avoid leakage of air through the joints

A

D) Avoid leakage of water through the joints

80
Q

Some of these advantages of electricity as a source of heat over other heating systems include the following except:
A) The operation of the heating devices is clean and silent
B) No combustion and combustion gases
C) The cost of installation is lower
D) The equipment requires more space
E) Individual room temperature control is easily obtained

A

D) The equipment requires more space

81
Q

In the electrostatic precipitator the positively charged dust particles are attracted to the metal ________ plates.
A) Ionizing
B) Parallel
C) Collector
D) Grounded
E) Neutral

A

C) Collector

82
Q

Calculate the relative humidity of a sample of air that at 21ºC (70ºF) holds 0.01 kg (0.022 lb) of moisture if the maximum that it can hold at this temperature is 0.015 kg (0.033 lb)
A) 25.8%
B) 93.3%
C) 66.7%
D) 10.7%
E) 0.33%

A

C) 66.7%

83
Q

Which one of the following factors affect the leakage tendency of a refrigerant?
A) Specific volume
B) Miscibility
C) Viscosity
D) Enthalpy
E) Temperature

A

C) Viscosity

84
Q

A refrigeration system using a high-pressure float provides for storage of the refrigerant in the:
A) Expansion valve
B) Receiver
C) Evaporator
D) Condenser
E) Compressor

A

C) Evaporator

85
Q

The amount of heat lost by conduction, convection, radiation, and infiltration is directly affected by the:
A) Room size
B) Room temperature
C) Angle of the sun
D) Ambient temperature
E) Wind velocity

A

E) Wind velocity

86
Q

Generally, positive displacement compressors favour:
A) Volume
B) Pressure
C) Time
D) Speed
E) Temperature

A

B) Pressure

87
Q

With a warm air heating system if there is insufficient heat throughout the building the trouble could be:
A) An adequate amount of air is supplied to all rooms and to provide good air distribution
B) The bonnet temperature is at least 65ºC (150ºF)
C) The thermostat is inaccurate
D) Occupied and unoccupied areas receiving adequate heat
E) Air filters are clean

A

C) The thermostat is inaccurate

88
Q

The first step in the procedure for replacing a faucet Bibb washer is:
A) Turn on the water supply
B) Shut off the supply of water at the nearest isolation valve
C) Remove the valve handle or wheel
D) Turn the faucet handle to a closed position
E) Unscrew the cartridge from the valve body

A

B) Shut off the supply of water at the nearest isolation valve

89
Q

Wear rings for a centrifugal pump can be installed on the:
A) Impeller or casing or both
B) Pump casing or shaft or both
C) Seal cage
D) Stuffing box
E) Pump shaft

A

A) Impeller or casing or both

90
Q

What is the symptom of a refrigeration system that has high suction pressure due to an oversized expansion valve?
A) Non-condensables in the system
B) An abnormally cold suction line
C) Fouled condenser
D) Contaminants in the refrigerant
E) Undersized compressor

A

B) An abnormally cold suction line

91
Q

What is the boiling temperature of R-134a (Freon 34a) at atmospheric conditions?
A) -26.1ºC (-14.98ºF)
B) -33.3ºC (-27.94ºF)
C) -40.8ºC (-41.44ºF)
D) 47.6ºC (117.68ºF)
E) 3.6ºC (38.5ºF)

A

A) -26.1ºC (-14.98ºF)

92
Q

One of the most common designs of a rotary compressor is the _________ type.
A) Axial flow
B) Positive displacement
C) Turbine
D) Centrifugal
E) Rotary screw

A

E) Rotary screw

93
Q

The purpose of the heat exchanger in a forced warm-air furnace is to exchange:
A) Combustion gas heat with air
B) Hot water heat with air
C) Air heat with combustion gases
D) Steam heat with air
E) Air heat with air

A

A) Combustion gas heat with air

94
Q

Three-way valves can be used in hydronic heating systems for ____________ service.
A) Agitating
B) Pressure
C) Diverting
D) Coagulating
E) Volume

A

C) Diverting

95
Q

The piping and heating units of a steam heating system must be so arranged that:
A) The condensate can flow freely from the boiler
B) Steam can flow freely to all heating units
C) The condensate can be returned freely to these units
D) The air can be contained in the heating units and piping
E) Steam can flow in insufficient quantities to all heating units

A

B) Steam can flow freely to all heating units

96
Q

Horizontal branch piping 76 mm (3 in) or less in diameter should have a minimum gradient of ___________ toward the stack.
A) 3cm/m (3/8 in/ft)
B) 4cm/m (1/2 in/ft)
C) 5cm/m (5/8 in/ft)
D) 2cm/m (1/4 in/ft)
E) 1cm/m (1/8 in/ft)

A

D) 2cm/m (1/4 in/ft)

97
Q

The operation of the compressor (starting, stopping, and unloading) is usually accomplished by a _________ type of actuated control.
A) Mass
B) Density
C) Volume
D) Level
E) Pressure

A

E) Pressure

98
Q

The fire point of oil is the temperature at which enough vapour is given off to:
A) Burn continuously
B) Ignite
C) Give off smoke
D) Ignite momentarily
E) Burst into flames

A

A) Burn continuously

99
Q

The moisture indicator is usually combined with the sight glass and it consists simply of a chemical dot placed under the glass lens so it is exposed to the liquid, and change in ___________ due to the presence of moisture is easily observed.
A) Temperature
B) Colour
C) Pressure
D) Heat
E) State

A

B) Colour

100
Q

All of the following methods are used to control the refrigeration compressor output except:
A) Hot gas bypass
B) Cylinder bypass
C) Cylinder unloaders
D) High-pressure float
E) Intermittent operation

A

D) High-pressure float

Comprehensive Review 5th Class Power Engineering (24 decks)

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