Power Eng Theory Chapters 90-95 and 104-109 Flashcards
1
Q
Sectional cast-iron boiler sections are connected with
a) push nipples
b) modules
c) Victaulic couplings
d) unions
e) threaded fittings
A
a) push nipples
2
Q
Cast-iron boiler sections maximize heat transfer by
a) utilizing as few passes as possible
b) vertical firing
c) exposing as large a surface as possible to the hot gases.
d) utilizing an external furnace
e) using four push nipples per section
A
c) exposing as large a surface as possible to the hot gases
3
Q
Boiler water legs
a) increase the heating surface
b) surround the furnace entirely
c) make water treatment less critical
d) support the boiler on concrete piers
e) make waterside maintenance easier.
A
a) increase the heating surface
4
Q
Boiler sections are held together with
a) cap bolts
b) torque tubes
c) pipe unions.
d) tie rods
e) stays
A
d) tie rods
5
Q
The ratio of heat released to heat transferred to boiler
water is known as
a) combustion efficiency
b) heating surface efficiency
c) boiler efficiency
d) section ratio
e) enthalpy transfer ratio
A
c) boiler efficiency
6
Q
Most low capacity cast-iron boilers
a) cannot be site assembled
b) can withstand higher pressures
c) will pass through standard size doorways
d) are factory assembled as packaged units
e) require special foundations
A
c) will pass through standard size doorways
7
Q
The steam and water spaces of a cast iron sectional boiler are connected by
a) tie rods
b) tie nipples
c) hydraulic jacks
d) steel studs
e) push nipples
A
e) push nipples
8
Q
The steam and water spaces of a cast iron sectional boiler are held together by
a) cast iron pipes
b) push nipples
c) steel studs
d) tie rods
e) push studs
A
d) tie rods
9
Q
In a vertical sectional boiler the sections are placed
a) one above the other
b) side by side
c) 45 degrees to each other
d) 90 degrees to each other
e) 180 degrees to each other
A
b) side by side
10
Q
The sections of cast iron boilers are mainly designed to
obtain maximum
a) water space
b) steam space
c) water circulation
d) heat transfer
e) steam output
A
d) heat transfer
11
Q
The fins cast on the flat surface of the sections of a cast iron sectional boiler are used for the purpose of increasing the
a) effectiveness of heat transfer
b) steam capacity
c) water capacity
d) water circulation
e) steam output
A
a) effectiveness of heat transfer
12
Q
To prevent flue gases from escaping in a cast iron sectional boiler, the spaces between the sections are sealed with high temperature
a) silicon chalking
b) foam insulation
c) plastic insulation
d) putty
e) asbestos rope
A
e) asbestos rope
13
Q
Heating boilers attain maximum efficiency only when they are operated
a) intermittently at 90% of the load
b) intermittently at half load
c) continuously at full load
d) continuously at half load
e) continuously at 75% of the load
A
c) continuously at full load
14
Q
Modular cast-iron boiler water flow is
a) continuous through all modules
b) connected in series
c) intermittent, occurring only while the unit is firing
d) always vertically upwards
e) done without the use of headers or manifolds
A
a) continuous through all modules
15
Q
In a cast iron modular heating boiler, the operation of the burner of each module is controlled by a __________ which starts or stops modules in sequence as load demand increases or decreases.
a) temperature sensor
b) step controller
c) thermostat
d) temperature transmitter
e) flow controller
A
b) step controller
16
Q
A cast-iron boiler disadvantage is
a) it is subject to corrosion
b) its difficult assembly
c) its extremely high cost
d) its high ductility
e) its pressure limitations
A
e) its pressure limitations
17
Q
A cast-iron boiler advantage is
a) its high factor of brittleness
b) light weight resulting in lesser foundation requirements
c) its ability to withstand high pressure
d) the choice of assembly location
e) their large capacity
A
d) the choice of assembly location
18
Q
Cast-iron boiler capacity
a) is very large compared to steel boilers
b) can be increased by simply adding sections
c) cannot be increased once assembly is completed
d) is not a function of section numbers
e) can be increased by increasing section size
A
b) can be increased by simply adding sections
19
Q
The reducing of oil into very small particles is termed
a) fluidization
b) fractionation
c) turbulence
d) atomization
e) distillation
A
d) atomization
20
Q
Before atomization can occur, heavy oils are heated to
approximately
a) 203 degrees C
b) 95 degrees C
c) 115 degrees C
d) 75 degrees C
e) 150 degrees C
A
b) 95 degrees C
21
Q
An air atomizing burner utilizes an air pressure of
approximately
a) 15 kPa
b) 150 kPa
c) 75 kPa
d) 95 kPa
e) 100 kPa
A
e) 100 kPa
22
Q
An air atomizing compressor is usually
a) a variable displacement type
b) a centrifugal type
c) an axial type
d) a positive displacement type
e) a regenerative type
A
d) a positive displacement type
23
Q
The capacity of a constant capacity mechanical atomizer is a function of
a) orifice size
b) pump speed
c) pump size
d) supply pressure
e) oil viscosity
A
a) orifice size
24
Q
A modulating pressure atomizer has its return oil flow
regulated by
a) a modulating valve to the burner
b) a modulating valve in the return line
c) a solenoid valve in the return line
d) a temperature control valve to the burner
e) pump speed
A
b) a modulating valve in the return line
25
To which of the following oil burners is the oil supplied under high pressure?
a) mechanical atomizing burner
b) air atomizing burner
c) rotary cup burner
d) steam atomizing burner
e) multi-spud burner
a) mechanical atomizing burner
26
When using mechanical fuel oil atomization
a) 70 kPa steam pressure is required at the burner
b) 35 to 40 kPa oil pressure is required
c) high pump pressure is required
d) steam pressure is required to keep the bypass open
e) dry saturated steam or superheated steam should be used
c) high pump pressure is required
27
Oil burners can be divided into three classes:
1. air and steam atomizing burners
2. mechanical or pressure atomizing burners
3. centrifugal or rotary cup burners
4. atmospherical pressure burners
5. gravitational pressure burners
a) 1, 2, and 3
b) 1, 2, and 4
c) 2, 3, and 4
d) 3, 4, and 5
e) 2, 3, and 5
a) 1, 2, and 3
28
The compressed air used as atomizing air in the air atomizing oil burner is also called
a) secondary air
b) primary air
c) pre-mixed air
d) pre-compressed air
e) post-copressed air
b) primary air
29
The two basic varieties of mechanical atomizing oil burners are:
1. variable capacity burner
2. constant capacity burner
3. modulating burner
4. stationary burner
a) 1 and 3
b) 2 and 3
c) 3 and 4
d) 1 and 5
e) 4 and 5
b) 2 and 3
30
A multi-burner cluster has secondary and tertiary nozzles ignited by
a) an igniter spark
b) an intermittent pilot flame
c) an interrupted pilot
d) the primary burner
e) a continuous pilot
d) the primary burner
31
When a greater than normal amount of combustible mixture is ignited the result may be
a) a boiler explosion
b) a puff-back
c) a negative furnace pressure
d) a too rapid boiler warm-up
e) liquid fuel entering the furnace
b) a puff-back
32
A fuel filter consists of
a) a cartridge
b) wool felt
c) three main parts
d) a Y-strainer
e) a canister
c) three main parts
33
Burner light oil supply pressure range is approximately
a) 50 to 100 kPa
b) 150 to 250 kPa
c) 300 to 550 kPa
d) 550 to 700 kPa
e) 700 to 850 kPa
d) 550 to 700 kPa
34
A relief valve is placed on the discharge of a fuel oil pump
a) because the pump is a dynamic type
b) so burner design pressure is not exceeded
c) so burner capacity is maintained
d) to prevent pump rupture
e) to prevent over-firing of the boiler
b) so burner design pressure is not exceeded
35
A time delay oil valve
a) opens when the pump starts
b) opens once ignition is verified
c) opens on flame failure
d) is located on the return line
e) is upstream of the pressure regulating valve
b) opens once ignition is verified
36
In order to prevent the possibility of a furnace explosion it is important that the furnace is __________ before the
igniter is energized and fuel is supplied to the burner
nozzle(s).
a) pre-heated
b) post-heated
c) purged
d) cooled
e) pressurized
c) purged
37
Intermediate and high fire burner nozzles have higher
capacities than the primary burner nozzle
a) to give greater firing variations
b) to prevent pressure surges
c) to prevent ignition puff-backs
d) because of the pump being of the positive displacement type
e) to allow better boiler warm-ups
e) to allow better boiler warm-ups
38
Oil flow rate to a modulating burner is regulated by
a) a return line modulating valve
b) a PRV on the burner line
c) pump speed
d) pump capacity
e) firing rate
a) a return line modulating valve
39
The minimum distance from furnace to oil storage tank is
a) 7 m
b) 5.2 m
c) 2.1 m
d) 4.7 m
e) 9.8 m
c) 2.1 m
40
Maximum static pressure in a fuel oil line is approximately
a) 10 kPa
b) 15 kPa
c) 80 kPa
d) 35 kPa
e) 70 kPa
e) 70 kPa
41
The main function of a gas burner is
a) atomization of the fuel
b) a source of ignition
c) provision of O2-fuel contact
d) regulation of the fuel flow
e) air flow control
c) provision of O2-fuel contact
42
An atmospheric burner has air entering around the burner which is termed
a) primary air
b) secondary air
c) atomizing air
d) combustion air
e) tertiary air
b) secondary air
43
The amount of pre-mix air to an atmospheric burner should be
a) 10 to 12%
b) 5 to 8%
c) 20 to 30%
d) 30 to 40%
e) 40 to 50%
d) 30 to 40%
44
A refractory burner disadvantage is
a) high initial cost
b) too much fuel preheat
c) low radiant heat
d) low combustion efficiency
e) overheating of boiler metal
a) high initial cost
45
A very popular packaged boiler gas burner is the
a) ring burner
b) non-articulated burner
c) post mix atmospheric burner
d) mechanical atomizing burner
e) cluster nozzle burner
a) ring burner
46
An atmospheric burner head which is very popular on heating boilers is the
a) refractory type
b) star type
c) ring type
d) rectangular type
e) ribbon ring type
d) rectangular type
47
When a gas fired burner is burning fuel properly
a) it will have a blue flame with short yellow tips
b) the furnace will pulsate
c) there will be no turbulence
d) it will have a long bright yellow flame
e) the induced draft fan can be shut off
a) it will have a blue flame with short yellow tips
48
Gas burners for heating boilers can be divided into two
general classes and they are the
a) pre and post turbulence burners
b) before and after burners
c) pre and post purge burners
d) pre and after mix burners
e) pre and post combustion burners
d) pre and after mix burners
49
The Venturi tube in the atmospheric burner mixing head has a
a) gradually decreasing cross-sectional area
b) gradually increasing cross-sectional area
c) sharply decreasing cross-sectional area
d) sharply increasing cross-sectional area
e) uniformly distributed cross-sectional area
b) gradually increasing cross-sectional area
50
__________ burner heads are most common for use in heating boilers.
a) Oval
b) Circular
c) Semi-circular
d) Triangular
e) Rectangular
e) Rectangular
51
One of the advantages of the refractory (gas) burner is the
a) low cost
b) gas and air mixture is thoroughly preheated before it
enters the furnace
c) flue gases are recirculated back to the furnace to
increase the furnace temperature
d) flue gases are thoroughly post-heated before they
leave the furnace
e) flame is directed to areas where it is needed the
most
b) gas and air mixture is thoroughly preheated before it
enters the furnace
52
The purpose of the deflector vanes in the centre of a ring (gas) burner is to
a) atomize the gas particles
b) increase the gas velocity
c) decrease the air velocity
d) promote turbulence of the gas and air mixture
e) increase the temperature of the furnace
d) promote turbulence of the gas and air mixture
53
One of the advantages of using natural gas as a fuel in a boiler is
a) that no storage space is required
b) the low cost
c) the abundance in supply
d) the portability
e) that no transmission lines are required
a) that no storage space is required
54
An intermittent pilot
a) lights the main flame then extinguishes
b) must be manually ignited
c) lights the main flame and remains on with it
d) remains on when the main flame extinguishes
e) lights a pilot flame then extinguishes
c) lights the main flame and remains on with it
55
The pilot burner for gas fired heating equipment can be:
1. manual
2. continuous
3. intermittent
4. interrupted
5. automatic
a) 1, 2, and 3
b) 2, 3, and 5
c) 2, 3, and 4
d) 3, 4, and 5
e) 1, 2, and 5
c) 2, 3, and 4
56
The __________ pilot is most often used on small boilers.
a) interrupted
b) intermittent
c) automatic
d) manual
e) continuous
e) continuous.
57
Large capacity burners
a) require high flow on ignition
b) are very safe relative to puff-back
c) require only a small pilot flame
d) should have minimum flow on ignition
e) are too hazardous and not recommended
d) should have minimum flow on ignition
58
A hydramotor valve
a) opens and closes quickly
b) helps to prevent puff-backs
c) uses air as its working medium
d) should not be the last fuel valve to open
e) closes slowly
b) helps to prevent puff-backs
59
A solenoid type fuel valve
a) is held closed by fuel pressure
b) always opens rapidly
c) is held closed by electrical current
d) closes slowly
e) does not have positive shut-off
a) is held closed by fuel pressure
60
If the power is cut off to an automatic gas valve, the valve will be
a) closed slowly
b) closed immediately
c) closed slightly
d) closed half-way
e) opened widely
b) closed immediately
61
The advantage of a motorized (hydramotor) gas valve is that the valve opens __________ thus preventing "furnace puff".
a) slowly
b) quickly
c) immediately
d) slightly
e) half-way
a) slowly
62
A function of a Bourdon tube gage hairspring is
a) return the tube to its zero position
b) keep the pointer on zero
c) eliminate backlash
d) return the pointer to zero
e) eliminate pointer linearity
c) eliminate backlash
63
An LP steam pressure gage range shall be between
a) 210 and 420 kPa
b) 300 and 450 kPa
c) 200 and 500 kPa
d) 210 and 460 kPa
e) 150 and 300 kPa
a) 210 and 420 kPa
64
An inspectors' test connection
a) should be located upstream of a siphon
b) should be of 12.7 mm NPT size
c) is required on all boilers
d) shall be located adjacent to the gage
e) is not mandatory on LP boilers
e) is not mandatory on LP boilers
65
When installing a siphon it
a) must be perpendicular to the piping
b) must be dry
c) should be downstream of an inspectors' test connection
d) should be first filled with water
e) shall be as close to the boiler as possible
d) should be first filled with water
66
An indication of a pressure gage not performing properly is
a) the needle fluctuating
b) the needle not returning to zero on depressurizing
c) a dial which rotates
d) a reading which is not the same as some other gage
e) the safety valve popping when gage reads normal
b) the needle not returning to zero on depressurizing
67
When using a dead weight tester, the effect of friction
a) is reduced by rotating the platform
b) will cause a higher than desired reading
c) is negligible
d) is eliminated with a lubricant
e) is compensated for mathematically
a) is reduced by rotating the platform
68
The working medium in the dead weight tester is
a) air
b) water
c) heavy oil
d) medium weight oil
e) alcohol
d) medium weight oil
69
An essential fitting between the boiler and the steam pressure gauge is
a) a check valve
b) a gate valve
c) a gage glass
d) a siphon
e) a steam trap
d) a siphon
70
A steam pressure gauge is graduated in
a) pascals
b) pascals per square metre
c) kilograms per square centimetre
d) kilograms per hour
e) kilopascals
e) kilopascals
71
The prime importance of boiler fittings are
a) economics
b) efficiency
c) safety
d) convenience
e) ease of operations
c) safety
72
All boiler fittings not properly or clearly identified should be
a) rejected
b) used for low pressure services only
c) used for low temperature services only
d) used for supplying low pressure water to softeners
e) accepted for a lower pressure or temperature rating
a) rejected
73
The purpose of the test connection on a boiler pressure gauge is to
a) unplug the siphon tube
b) test a sample of steam for purity
c) install the boiler inspector's pressure gauge
d) inject live steam to the gauge
e) vent air from the pressure gauge
c) install the boiler inspector's pressure gauge
74
As the boiler pressure increases, the bourdon tube of the pressure gauge will
a) tend to straighten
b) compress more
c) become less circular in cross-section
d) become smaller in diameter
e) tend to twist
a) tend to straighten
75
The cross-section of a Bourdon tube is generally
a) circular
b) round
c) cylindrical
d) spherical
e) oval
e) oval
76
An essential fitting between the boiler and the steam
pressure gauge is a
a) check valve
b) gate valve
c) gauge glass
d) siphon
e) steam trap
d) siphon
77
The purpose of the pipe siphon installed between the boiler and the pressure gauge is to prevent
a) air from entering the gauge
b) water from entering the gauge
c) hot steam from entering the gauge
d) air from entering the boiler
e) hot steam from entering the boiler
c) hot steam from entering the gauge
78
According to the ASME code, the scale on the dial of the steam gauge for a low pressure steam heating boiler shall be graduated to not less than
a) 210 kPa
b) 420 kPa
c) 510 kPa
d) 640 kPa
e) 720 kPa
a) 210 kPa
79
According to the ASME code, the scale on the dial of the steam gauge for a low pressure steam heating boiler shall be graduated to not more than
a) 210 kPa
b) 420 kPa
c) 510 kPa
d) 640 kPa
e) 720 kPa
b) 420 kPa
80
An LP steam boiler safety valve shall not be smaller than
a) 110 mm
b) 12.7 mm
c) 76 mm
d) 25.4 mm
e) 101.6 mm
b) 12.7 mm
81
In order to ensure a safety valve seats properly, it uses
a) seat rings
b) a huddling chamber
c) a blowdown ring
d) guides and bushings
e) a test lever
d) guides and bushings
82
The force of the steam pressure acting on the safety valve disc is a function of
a) disc area
b) huddling chamber volume
c) seat diameter
d) percent valve opening
e) blowdown ring diameter
a) disc area
83
The minimum blowdown of an LP safety valve is
a) 96% of the set pressure
b) 5% of the set pressure
c) 14 kPa
d) 2 kPa
e) 101.3 kPa
c) 14 kPa
84
Popping pressure of an LP safety valve may be adjusted
a) any amount
b) no more than the allowed blowdown
c) up to 5%
d) up to 7.5%
e) by anyone
c) up to 5%
85
The blowdown on a safety valve is adjusted by turning the
a) inspector's seal
b) valve disc
c) adjusting nut
d) adjusting ring
e) valve seat
c) adjusting nut
86
What does the boiler inspector install to prevent tampering with a safety valve setting?
a) a restraining order
b) a gag
c) a seal
d) a plug
e) a cover plate
c) a seal
87
The lip on a safety valve
a) allows it to close slowly
b) is only required if the steam is superheated
c) supplies a drain lip for condensate to collect on
d) makes the valve stronger
e) allows it to "pop" open
e) allows it to "pop" open
88
A safety valve on a steam heating boiler must not be smaller than
a) 25 mm
b) 19 mm
c) 38 mm
d) 13 mm
e) 30 mm
d) 13 mm
89
According to the ASME code, steam heating boilers shall have one or more safety valves, adjusted and sealed to discharge at a pressure not exceeding __________ kPa.
a) 100
b) 101
c) 110
d) 103
e) 105
d) 103
90
According to the ASME code, the valve seat diameter of the safety valve on a steam heating boiler must not be smaller than
a) 12.7 mm (1/2 in.)
b) 25.4 mm (1 in.)
c) 38.1 mm (1 1/2 in.)
d) 50.8 mm (2 in.)
e) 63.5 mm (2 1/2 in.)
a) 12.7 mm (1/2 in.)
91
According to the ASME code, the valve seat diameter of the safety valve on a steam heating boiler must not be larger than
a) 25.4 mm (1 in.)
b) 38.1 mm (1 1/2 in.)
c) 50.8 mm (2 in.)
d) 63.5 mm (2 1/2 in.)
e) 110 mm (4 1/2 in.)
e) 110 mm (4 1/2 in.)
92
For a steam heating boiler, the safety valve shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than ___________ kPa above the maximum allowable working pressure when all steam outlets are closed.
a) 103
b) 101
c) 100
d) 55
e) 34
e) 34
93
The safety valve shall be installed in __________ position and located in the highest practicable part of the boiler
proper.
a) the highest
b) the lowest
c) a mid
d) a vertical
e) a horizontal
d) a vertical
94
An LP safety valve lever test should be performed
a) weekly
b) semi-annually
c) monthly
d) daily
e) quarterly
c) monthly
95
LP boiler safety valves can be repaired
a) only when authorized by the inspector
b) by anyone qualified to do so
c) by a qualified boiler operator after permission from the inspector
d) by a licensed boiler operator
e) by only the manufacturer
c) by a qualified boiler operator after permission from the
inspector
96
An operator should check that a boiler safety valve will open at its set pressure by
a) sending for the inspector to bring his or her test gage
b) increasing the boiler pressure until the valve opens and noting the pressure on the pressure gage when the valve opened
c) putting a piece of pipe over the lifting lever and lifting the valve off its seat when the seat pressure is reached
d) connecting the boiler to an air compressor during shut down and raising the pressure in the boiler until the set pressure is reached
e) listening to the alarms of the set pressures
b) increasing the boiler pressure until the valve opens and
noting the pressure on the pressure gage when the valve opened
97
Testing the safety valve by means of the try lever method, is considered good practice when carried out on a
a) weekly basis
b) monthly basis
c) six monthly basis
d) yearly basis
e) bi-weekly basis
b) monthly basis
98
If a safety valve leaks after a try lever test, the operator
should
a) plug the safety valve outlet
b) reduce the boiler pressure
c) operate the try lever several times to blow away foreign material
d) fit a gag to the safety valve
e) reduce boiler pressure and call the team leader
c) operate the try lever several times to blow away foreign
99
If you found the safety valve on your heating boiler stuck in the closed position while the boiler was in operation, the best thing to do is
a) tap it gently with a bronze hammer to free it
b) reduce the boiler pressure and continue operating
c) report it to the shift team leader
d) shut down the boiler and repair or replace the safety valve
e) put the boiler on hand control and notify the inspector
d) shut down the boiler and repair or replace the safety valve
100
LP steam boilers must be equipped with a marker indicating the
a) maximum water level line
b) low water fuel cut-off line
c) lowest permissible water line
d) lowest visible water line
e) fireline
c) lowest permissible water line
101
A gage glass may be surrounded by a number of thin rods
a) when the boiler is a high pressure unit
b) to protect the operator from injury
c) to prevent cold draft damage
d) to protect the glass from damage
e) if the glass is attached to a water column
d) to protect the glass from damage
102
Quick-closing gage glass valves
a) prevent loss of water automatically should glass rupture
b) should be installed on all boilers
c) will not permit gage glass blowdown
d) are designed to prevent operator injury
e) require 90 degrees for full travel
e) require 90 degrees for full travel
103
A disadvantage of a gage glass safety-shutoff valve is
a) the glass cannot be blown down
b) it requires more maintenance
c) it cannot withstand high pressure
d) loss of water is not prevented
e) it makes gage glass replacement more difficult
b) it requires more maintenance
104
Should the steam line or water line to a gage glass become plugged with sludge
a) gage glass level will drop in both cases
b) gage glass level will drop in the first case and rise in
the second
c) gage glass level will remain where it was
d) the gage glass will read high
e) gage glass level will rise in the first case and drop in
the second
d) the gage glass will read high
105
Water column supply line crosses will
a) permit piping inspection
b) allow for piping cleaning and inspection
c) replace safety shut-off valves
d) be installed only on boilers not under continuous
supervision
e) prevent gage glass blowout
b) allow for piping cleaning and inspection
106
Gage glass rupture may be caused by
a) maximum allowable boiler pressure
b) a cold draft
c) a sudden pressure drop
d) warming the boiler up too quickly
e) improper boiler water treatment
b) a cold draft
107
When gage glass nuts are leaking
a) the gage glass should be replaced
b) they should be tightened immediately
c) new packing should be installed
d) the glass should be isolated and depressurized before tightening
e) they should be replaced
d) the glass should be isolated and depressurized before
108
When the water connection between boiler and gage glass becomes plugged, the water level in the glass will show a level after a while, that is
a) higher than the level in the boiler
b) lower than the level in the boiler
c) the same as the level in the boiler
d) fully filled
e) lower than the bottom of the sight glass
a) higher than the level in the boiler
109
The lowest visible part of the water gauge glass shall be at least __________ mm above the lowest permissible water level recommended by the manufacturer.
a) 25
b) 50
c) 75
d) 100
e) 125
a) 25
110
The ASME code states that each steam boiler shall have one or more water gauge glasses attached either directly to the boiler or to a water column by means of valve fittings not less than __________ mm pipe size.
a) 75
b) 51
c) 24
d) 13
e) 10
d) 13
111
On a multiple steam boiler heating system, a stop valve must be placed at each boiler outlet to
a) permit slower system warm-ups
b) allow boiler isolation from the system
c) prevent steam from entering another boiler
d) allow each boiler to supply only a part of the system
e) permit different system pressures
b) allow boiler isolation from the system
112
Boiler outlet valves are usually
a) gate valves because of their low resistance to flow
b) gate valves because of the ability to control flow
c) globe valves because of their throttling capability
d) globe valves because of their low flow resistance
e) installed in tandem
a) gate valves because of their low resistance to flow
113
An outside screw and yoke valve
a) is always a gate valve
b) readily shows its operating position
c) is difficult to lubricate
d) requires no packing
e) has a non-rising stem
b) readily shows its operating position
114
The quick closing valves on the water gauge requires only a/an __________ of a turn of the valve spindle to change the valve from the full open to the full closed position and viceversa.
a) eighth
b) quarter
c) one-third
d) fifth
e) half
b) quarter
115
The feedwater pipe, before it enters the boiler must be
fitted with a __________ valve adjacent to the boiler.
a) stop
b) gate
c) globe
d) check
e) plug
d) check
116
A boiler feedwater stop valve
a) should never be used to control water level
b) is used to isolate the deaerator
c) should be a globe valve
d) should be located close to the feedwater pump
e) is used to isolate the feedwater line
e) is used to isolate the feedwater line
117
A globe valve should be used in the feedwater line
a) at all times
b) whenever it may be used for control purposes
c) if it is of the OS&Y type
d) when the system is of multiboiler installation
e) because of its low flow resistance
b) whenever it may be used for control purposes
118
A stop valve is fitted between the boiler and the feed water check valve
a) to regulate the feedwater to the water column
b) for isolation and to provide a positive shut-off
c) if the boiler is a hot water boiler
d) if the boiler is gas fired
e) to provide feed water regulation to the boiler
b) for isolation and to provide a positive shut-off
119
Boiler water foaming may be the result of
a) low pH
b) excessive blowdown
c) low TDS
d) high TDS
e) dissolved gases
d) high TDS
120
Boiler blowdown lines have a specific size range based on
a) water impurities
b) the amount of blowdown required
c) boiler capacity
d) operating pressure
e) line length
c) boiler capacity
121
Boiler blowdown piping
a) can be reduced in size after the blowdown valves
b) must be full size to the point of discharge
c) must be at least 51 mm in size
d) can have valves of a smaller size than piping
e) may discharge to the sewer system
b) must be full size to the point of discharge
122
A steam boiler is blown down in order to
a) clean the soot and carbon out of the firebox and tubes
b) lower the operating water level in the boiler
c) discharge sediment and scale forming matter from the boiler
d) test the rated relieving capacity of the safety valves fitted to the boiler
e) locate the steam level
c) discharge sediment and scale forming matter from the boiler
123
The purpose of the small vent valve or cock located on top of the shell or on top of the water column on most boilers is
a) to allow water to escape from the boiler when the boiler is being filled with air
b) to allow air in to the boiler when the boiler is being
filled with water
c) to allow water to escape before the steam stop valve is opened during the warm-up period
d) to allow air to escape from the boiler when the boiler is being filled with water
e) to allow water into the boiler when the boiler is being drained or cooled preventing the formation of a vacuum
d) to allow air to escape from the boiler when the boiler is being filled with water
124
A pressure or altitude gage for a hot water boiler
a) must be equipped with a siphon
b) shall have a dial scale at least 3 times the maximum
allowable working pressure
c) does not require a siphon
d) must have a temperature dial
e) must be of 51 mm pipe size
c) does not require a siphon
125
When a closed expansion tank is used and the system is cold
a) the auto fill valve will maintain a system minimum pressure
b) the tank level will be high
c) there will be no air in the tank
d) the possibility of air in the system will be high
e) the tank should be manually filled
a) the auto fill valve will maintain a system minimum pressure
126
An altitude gage on hot water heating boilers is used to indicate
a) expansion tank temperature
b) boiler temperature
c) furnace draft
d) height of the highest radiator in system
e) the height of the boiler
d) height of the highest radiator in system
127
Siphon is not required between a pressure or an altitude gauge and a hot water boiler since these boilers are
a) filled with steam
b) partially filled with steam
c) partially filled with air
d) filled with water
e) filled with water and air mixtures
d) filled with water
128
The lever handle of the shut-off cock between a pressure or altitude gauge and a hot water boiler should be __________ to the pipe in which it is located when the cock is open.
a) perpendicular
b) parallel
c) adjacent
d) opposite
e) tangent
b) parallel
129
The scale on the dial of a pressure gauge should be graduated to not less than __________ times the maximum allowable working pressure.
a) 1.5
b) 2.0
c) 2.5
d) 3.0
e) 3.5
a) 1.5
130
The dial of a pressure gauge on a hot water boiler indicating SI units can be graduated in
a) metres of mercury
b) mm of water
c) mPa
d) psi
e) kPa
e) kPa
131
When the pressure pointer of a closed system reads lower than the altitude pointer the
a) system is full of water
b) expansion tank level will be high
c) boiler is being over-fired
d) gage is faulty
e) system requires water
e) system requires water
132
The temperature indicator of a hot water boiler should
indicate water temperature
a) at the boiler inlet
b) in the expansion tank
c) midway through the system
d) at the boiler outlet
e) in the boiler
d) at the boiler outlet
133
On a pressure temperature indicator, if the pressure pointer falls below the altitude pointer
a) the atmospheric pressure is low
b) the system is low on water
c) the boiler is too full
d) the water is too hot
e) the water is too cold
b) the system is low on water
134
Hot water heating boilers must be equipped with a
a) thermometer
b) fusible plug
c) return trap
d) blow down tank
e) steam pressure gage
a) thermometer
135
With the fusible plug type of temperature relief device, the fusible plug will melt at __________ degrees Celsius and allow hot water to escape.
a) 131
b) 121
c) 101.3
d) 100
e) 99
e) 99
136
The expansion and contraction rod type of temperature relief device will open the valve at __________ degrees Celsius and close it at __________ degrees Celsius.
a) 99 and 80
b) 100 and 71
c) 101.3 and 75
d) 99 and 71
e) 100 and 80
d) 99 and 71
137
A boiler pressure relief valve
a) shall be installed on the boiler
b) can be installed anywhere in the system but preferably close to the expansion tank
c) must be at least 51 mm pipe size
d) does not require annual checking or testing
e) can be installed with an isolation valve
b) can be installed anywhere in the system but preferably
138
For hot water boilers operating up to 414 kPa, a pressure relief valve opening pressure variation may be as much as
a) 14 kPa
b) 5%
c) 14%
d) 5 kPa
e) 10%
a) 14 kPa
139
A hot water boiler is protected from over pressure by means of
a) a safety pop valve
b) a high limit pressure control
c) an expansion valve
d) an air release valve
e) a safety relief valve
e) a safety relief valve
140
ASME Section IV, states that each hot water heating boiler shall have at least one officially rated pressure relief valve set to relieve at or __________ the maximum allowable working pressure of the boiler.
a) below
b) 6% above
c) 1.5 times
d) twice
e) 10% above
a) below
141
Hot water boilers have stop valves in their inlet and outlet piping
a) to allow for better warm-ups
b) to prevent water from entering another in-service unit
c) so that each boiler can have separate water treatment
d) to permit annual maintenance
e) so that the boiler can be drained without draining the system
e) so that the boiler can be drained without draining the system
142
Boiler stop valves shall be
a) of the OS&Y type
b) globe valves
c) identified with durable tags
d) installed on horizontal piping
e) throttled during operation
c) identified with durable tags
143
During warm-up of a cold hot water boiler excessive pressurebuild-up is prevented by
a) a very slow warm-up
b) an expansion tank
c) a pressure relief valve
d) opening the boiler outlet valve
e) venting the system
b) an expansion tank
144
In a closed expansion tank system an air separator
a) removes air from the system
b) is installed at the boiler inlet
c) is installed at the boiler outlet
d) directs air into the expansion tank
e) is not required
d) directs air into the expansion tank
145
In a hot water heating system, the closed type expansion tank should be
a) kept full of water
b) open to the atmosphere
c) partly filled with water
d) isolated from the system
e) closed and independently heated
c) partly filled with water
146
When a closed type expansion tank on a hot water boiler is completely filled with water and the water in the system is raised in temperature so that it expands, the result will be that
a) the boiler expands
b) the pressure build-up opens the safety relief valve
c) the heating system becomes noisy
d) the circulating pump will stop
e) the expansion tank will expand
b) the pressure build-up opens the safety relief valve
147
An expansion tank is used to
a) store steam
b) increase water temperature
c) allow for the expansion of the water
d) provide more efficient water circulation
e) allow free expansion of the steam
c) allow for the expansion of the water
148
The head of water in the hot water heating system employing an open type of expansion is referred to the vertical
distance from the gauge of the boiler to the level in the
__________, which is considered the highest level of the water in the system.
a) steam drum
b) top row of tubes
c) auto-fill valve
d) expansion tank
e) hot water outlet valve
d) expansion tank
149
An automatic fill valve
a) will maintain maximum system pressure at all times
b) is a mandatory fitting
c) is not mandatory
d) opens only when expansion tank level is low
e) can be used with an open tank system
c) is not mandatory
150
A closed expansion tank is usually equipped with
a) a gage glass
b) a pressure relief valve
c) an automatic fill valve
d) a circulating pump
e) a thermometer
a) a gage glass
151
Before starting up a new boiler or one that has been out of service the following must be ensured
a) the manufacturer's recommendations are read
b) the boiler has a valid inspection certificate
c) the fuel is shut off
d) the boiler control is in the OFF position
e) the boiler is cold
b) the boiler has a valid inspection certificate
152
It is very important that boilers should be
a) warmed up quickly to prevent condensation
b) warmed up quickly to prevent scale build-up
c) lit only when cool
d) warmed up slowly to prevent thermal shock
e) warmed up at a rate of one degree every five minutes
d) warmed up slowly to prevent thermal shock
153
When cutting in an additional boiler into the heating system
a) the stop values in the supply and return lines are both closed
b) the supply valve is open slightly, the return line closed
c) the supply and return lines are open
d) the supply valve only is closed
e) the supply and return line valves are both open slightly
a) the stop values in the supply and return lines are both
154
One of the most important points that should be observed before a new boiler is started and put into continuous operation is to
a) check and make sure all valves are opened
b) check and make sure all valves are closed
c) make sure the vent is in the open position
d) make sure the inspection certificate is valid
e) make sure the startup is on schedule
d) make sure the inspection certificate is valid
155
When preparing a boiler for startup and the boiler is
equipped with a modulating combustion control, it is best to
a) set the manual-auto switch to "auto"
b) set the manual-auto switch to "auto" and set the flame control switch in the lowest position
c) set the manual-auto switch to "auto" and set the flame control switch in the highest position
d) set the manual-auto switch to "manual" and set the flame control switch in the lowest position
e) set the manual-auto switch to "manual" and set the flame control switch in the highest position
d) set the manual-auto switch to "manual" and set the flame
156
If the low-water fuel cutoff and/or the high limit control
are equipped with a trip-out device on a boiler, it is
recommended as part of the startup preparation to
a) dismantle the device and check for lose wires
b) push the reset button to assure that the switches are closed
c) check the low-water fuel cutoff and make sure all the
mercury switches are working properly
d) check that the high limit switches are set high enough
e) dismantle the high limit switches and overhaul if
necessary
b) push the reset button to assure that the switches are closed
157
In hot water boiler operation the maximum operating
temperature should never exceed
a) 77 degrees C
b) 87 degrees C
c) 100 degrees C
d) 121 degrees C
e) 131 degrees C
d) 121 degrees C
158
The pressure relief valve on a hot water heating boiler
should be set
a) 25% lower than operating pressure
b) 10% lower than operating pressure
c) 25% above operating pressure
d) 20% lower than operating pressure
e) at the operating pressure
c) 25% above operating pressure
159
A gradual increase in stack temperature is an indication of
a) poor burner operation
b) too much excess air
c) unclean heating surfaces
d) poor damper operation
e) all of the above
c) unclean heating surfaces
160
The discharge pressure of steam heating pressure relief valves should never exceed
a) 14.7 kPa
b) 121 kPa
c) 93 kPa
d) 103 kPa
e) 153 kPa
d) 103 kPa
161
How often would you test the low level fuel cut-off on a low pressure steam heating boiler by blowing out the float chamber?
a) daily
b) monthly
c) semi-annually
d) annually
e) bi-weekly
a) daily
162
The maximum pressure of a low pressure steam heating boiler is
a) 70 kPa
b) 103 kPa
c) 113 kPa
d) 207 kPa
e) 1104 kPa
b) 103 kPa
163
The maximum operating temperature of a hot water heating boiler is
a) 100 degrees Celsius
b) 120 degrees Celsius
c) 200 degrees Celsius
d) 121 degrees Celsius
e) 160 degrees Celsius
d) 121 degrees Celsius
164
Should any abnormal condition occur during light-off or the temperature building-up period
a) continue to run the boiler but reduce the steam and fuel valve settings
b) stop running the boiler immediately and open the vent valve
c) stop running the boiler immediately and open the
feedwater valve
d) continue to run the boiler but reduce the load and close the steam valve
e) shut down the boiler immediately and close the stop
valves in the fuel lines
e) shut down the boiler immediately and close the stop
| valves in the fuel lines
165
There are two conditions that may occur during the warm up period which may seem to be abnormal to the operator but will disappear after the boiler heats up. These conditions are
a) uneven expansion and thermal shock
b) fluctuation of water and steam pressures
c) slight smoking and condensation
d) high stack and hot water/steam temperature
e) low stack and hot water/steam temperature
e) low stack and hot water/steam temperature
166
During the warm-up period of a heating boiler the main burner goes out. The operator should
a) shut down the boiler immediately, purge the boiler, and restart it.
b) shut down the boiler, close the fuel valves, and
determine the cause of the problem
c) try to re-light the burner immediately
d) check the altitude gage to ensure there is enough water in the system
e) clean the burner, purge the boiler, and restart it
b) shut down the boiler, close the fuel valves, and
| determine the cause of the problem
167
Thermal shock to boilers can be reduced by
a) warming up boilers slowly
b) keeping the boiler free of scale build-up
c) covering the tube sheets with refractory
d) not allowing full flow of cold water into a warm hot
water boiler
e) all of the above
e) all of the above
168
The most important rule in safe operation of a steam heating boiler is
a) operate the burner properly
b) keep the water level in the boiler at the proper level
c) maintain the proper operation of automatic controls
d) maintain the correct level in the altitude gage
e) ensure air is kept out of the system
b) keep the water level in the boiler at the proper level
169
To reduce the effects of uneven expansion and thermal shock and to protect a boiler against damage during startup, one of the precautions that should be taken is
a) always heat up the boiler quickly
b) always warm up the boiler slowly
c) make sure the vent is opened
d) make sure the steam is closed
e) always open the fuel valve slowly
b) always warm up the boiler slowly
170
It is recommended that the differential between the safety relief valve set pressure and the operating pressure of a hot water boiler be kept to a minimum of 69 kPa (10 psi) or __________ % of the relief valve setting.
a) 10
b) 15
c) 20
d) 25
e) 30
d) 25
171
Smoking conditions during the operation of a boiler can be caused by
a) improper air/fuel ratio
b) steam demands too great
c) low water conditions
d) too much combustion air
e) not enough fuel
a) improper air/fuel ratio
172
A cast iron boiler advantage is:
The choice of assembly location and high resistance to corrosion and larging boiler capacity
173
Cast iron boiler sections maximize heat transfer by:
Exposing as large a surface as possible to the hot gases
174
A cast iron boiler disadvantage is:
Its pressure limitations.
175
Low pressure boilers are made of:
steel and cast iron
176
Boiler water legs:
Increase the heating surface
177
Modular cast iron boiler water flow is:
Continuous through all modules
178
Most low capacity cast iron boilers:
Will pass through standard size doorways
179
Cast iron boiler capacity:
Can be increased by simply adding sections
180
An air, atomizing compressor is usually:
A positive displacement type
181
A fuel filter consists of:
Three main parts
182
A time delay oil valve:
Opens 5 to 15 seconds after ignition
183
An air, atomizing burner utilizes an air pressure of approximately:
100 kPa.
184
When using mechanical fuel oil atomization:
High pump pressure is required
185
Heating plants with multiple boilers often have:
Independent boiler feedwater controls from a header
186
Dissolved oxygen in condensate:
Will cause pitting in a boiler
187
Because of variations in flow rate, nearly all, large steam heating plants utilize:
A condensate receiver
188
A float operated mechanical feeder valve should:
A) be a normally closed valve
B) not be deemed a stand-by device
C) open just after the low-water cut-off switch opens
D) not open until the level is well below the feed pump cut-in level
E) be located above the water column
Verificar
D) not open until the level is well below the feed pump cut-in level
189
A feedwater make-up system should:
Be able to satisfy normal firing needs
190
Equalizing lines on a condensate receiver float chamber:
Will dampen level fluctuations
191
A condensate receiver low, level cutoff switch will:
Stop the feed pump thereby preventing damage to it
192
An electric feeder valve will:
Open before the low-water cutoff line is reached
193
The result of a condensate receiver that is too small could be:
Loss of condensate to the sewer
194
In nearly all LP steam heating systems the feedwater:
Is usually condensate
195
When a boiler equipped with a combination feedwater control and low water cutoff device shuts down due to a low water condition:
The level must be restored to above the cutoff line before the unit can be restarted
196
The Hartford loop will:
Prevent boiler water level from going below the lowest safe water level.
197
Neutralizing amines:
Raise the pH of condensate
198
The feedwater supply to most heating boilers is controlled by a _____ switch.
Float
199
As a general rule the size of the condensate receiver should be large enough to hold a volume of condensate equal to the water evaporated by the boiler in a _____ hour period.
One half.
200
The feedwater pipe before entering the boiler must contain:
A check valve with with a stop valve between the check valve and the boiler
201
When a cutting in an additional boiler to a heading system once the boiler temperature reaches the supply main temperature the:
respuesta a validar
202
If the power is cut off to an automatic gas valve, the valve will:
Close immediately
203
A close type expansion tank in a hot water heating system must:
Be partially filled with air at all times
204
A closed type expansion tank in a hot water heating system must:
Be partially filled with air at all times
205
A fitting that is not clearly identified should be
Rejected completely
206
The purpose of the test connection on a boiler pressure gauge id to:
Install boilere s inspector pressure gauge
207
before the try lever test ona water system operating above 60 C is attempted the operator must ensure that:
The pressure is at least 75% of the valve set pressure
208
When warming up a hot water boiler in preparation for service, in parallel with other boilers in a heating system
The supply valve is open slightly, the return line is closed
209
Hot water heating boilers have stop valves in their inlet and outlet piping
So that the boiler can be drained without draining the system
210
Rust in the water gauge glass is an indication that:
Corrosion is occurring in the system
211
Slight smoking during the start-up of a cold oil-fired boiler is caused by:
Oil furnace temperatures not yet up to operational parameters
212
When a somewhat greater than normal amount of combustible mixture is ignited, the result may be:
A puff-bank
213
The main function of a gas burner is:
Provision of air fuel contact
214
When cutting in an additional boiler into a heating system once the boiler temperature reaches the supply main temperature the:
- Supply and return lines are open
- Supply and return line valves are both open slightly
- Stop valves in the supply and return lines are both closed
- Supply valve is open slightly and the return lines is closed
- Supply valve only is closed
- Supply valve only is closed
215
Which of the following devices may indicate that there is a leak in a hydronic heating system equipped with an automatic fill valve?
Water flow meter
216
According to the current code the scales on a pressure gage for a steam heating boiler, shall be garduated between one of the following:
From 200 to 414 kPa
217
The main function of a gas burner is to:
a) Shoot the gas into the furnace
b) Provide intimate mixing of gas with combustion air
c) Regulate the gas flow into the furnace
d) Regulate the amount of excess air
e) Consume the combustion air
b) Provide intimate mixing of gas with combustion air
218
A closed expansion tank is usually equipped with:
- A gauge glass
- An automatic fill valve
- A circulating pump
- A thermometer
- A pressure relief valve
- A gauge glass
219
Current code states that the feedwater pipe, before it enters the boiler, must be fitted with a _________ valve adjacent to the boiler
Stop
220
Each hot water heating boiler shall be equipped with stop valves in the supply and return connections to:
Drain off the boiler without emptying the system
221
Hot water heating boilers have stop valves in their inlet and outlet piping:
So that the boiler can be drained without draining the system
222
A modulating control steam heating boiler
has very efficient operation
223
An ON-OFF steam boiler:
Operates most efficiently at continuous firing
224
Thermocouples are connected in series to:
generate a higher voltage
225
Deviation is the difference between the set point of a controller and the value of the controlled variable. It is also called:
offset
226
A manual HIGH-LOW switch should be switched to high or AUTO
When the boiler has been properly warmed-up
227
In electric switch configuration the term contact arrangement refers to:
Normally open or normally closed position
228
A high limit control switch
Must be used when a boiler is not under continuous supervision
229
An example of a controlled device would be a:
Motor operating air dampers
230
A flame failure device
Will shut-off the fuel to the burner
231
Because of variations in flow rate, nearly all, large steam heating plants utilize
A condensate receiver
232
the type of combustion fuel control frequently used on a small packaged boiler is a/an:
On-Off control
233
A device used to position dampers and control valves is termed a/an:
Actuator
234
```
The effective range of a control pressure used in 103 kPa circuits is usually considered to be from:
A) 0 to 100 kPa
B) 20 to 90 kPa
C) 2 to 25 kPa
D) 3 to 15 kPa
E) 5 to 75 kPa
```
Verificar
| no es de 20 a 90
235
Quickly closing the main burner manual valve during boiler operation should check the:
Buscar la opcion correcta
A) combustion air proving switch
C) high gas pressure fuel cut-off
D) low gas pressure fuel cut-off
E) flame scanner
236
an advantage of an electronic control system is that
The controllers can accept a wide variety of inputs
237
in a basic electrical control system the device that senses a drop in air temperature is called the:
Thermostat
238
An electronic controller is:
Used to position an actuator
239
One type of flame failure device uses a lead sulphide cell that is sensitive to
infrared rays
240
An example of a final control element is a:
Damper
241
on a multi-burner boiler HIGH fire nozzle will:
Operates continuously when steam demand exceeds boiler capacity
242
Pneumatic controllers are divided into two basic classes:
Bleed and non-bleed
243
The most common type of damper operator is
piston
244
an electrical control system is comprised of a:
sensor, controller, and final control element
245
in a self-contained control system the energy for operation is provided by:
The reaction of the sensing device
246
the bimetal sensing element consists of a strip made up of two thin layers of metal with:
Widely different rates of thermal expansion
247
__________________is the term that refers to the normal electric supply voltage
Line voltage
248
The sections in a cast iron boiler are sealed using
High temperature rods
249
the fuel oil supply pressure in a modulating burner and pilot system is approximately
1380 kPa
250
A hydramotor valve
opens slow and closes quickly
251
Large size solenoid type valve open wide in approximately _______seconds to prevent a furnace puff
4 to 5
252
The piston in a motorized gas valve is closed by
a) Loss of power
b) release of hydraulic fluid
c) Spring action
d) all of the above
d) all of the above
253
A function of a bourdon tube gauge hairspring is to:
keep the pointer on zero
254
According to the ASME Code section IV, steel or raught iron pressure gauge connections must be not less than?________ pipe size
NPS 1/2 (DN 15)
255
an outside screw and yoke valve
Rarely shows its operating position
256
how are stop valves used on outlet connections of heating boilers identified
With metal tags
257
In a closed expansion tank system an air separator will:
direct air into the expansion tank
258
The minimum temperature at which a hot water heating boiler should be operated to prevent condensation is
77 degrees C
259
The cut-off switch opens and cut-off power to the fuel valve when the boiler level in the glass show at least______ of water.
20 mm
260
A small steam heating boiler with a combination low water cut off and feed water control must, by code, have a second dedicated:
low water cut off
261
In a well balanced steam system with condensate return:
Steam produces equal condensate return
262
A modulating control steam heating boiler
maintains a steady boiler pressure
263
A low fired switch
is part of the start logic system
264
the type of burners required for high low fire control are
Multiple nozzles
265
When a boiler is shut down on the high limit control, what must the operator do before starting the boiler up again
Reset the lockout on the high limit controllers
266
Flame rods:
shut off the fuel within 4 sec of flame failure
267
The outter shiath of a thermocouple used with a pilot burner is made of
Copper
268
A photo self detection device is often called a :
Scanner
269
the maximum temperature for a lead sulphide scanner is:
50 degrees C
270
A pneumatic control system:
Uses a sensing device to change pressure in the control line
271
A pneumatic rely can also be called a:
Cumulator
272
A pneumatic control system consists of:
a) thermostat and humidistats
b) air, piping and tubing
c) air compressor system
d) all of the above
d) all of the above
273
When the control pressure in a pneumatic controller is either as maximum or minimum without any intermediate steps, the control is
on-off
274
The piston is sealed to avoid air leakage in a piston type damper operator by using:
Rolling diaphragm
275
In a capacity type controlled motor, the rotor of and gear train are sealed inside a housing that is partially filled with
Oil
276
which of the following types of switching devices are used in conjoction with by-metal strips to control electric circuits
a) Open contact switch
b) Mercury bolt switch
c) Snap switch
d) All of the above
d) All of the above
277
a heat anticipator gives a thermostat timed ____ position action to prevent the room tempeature to overshooting
Two
278
types of metals used to manufactured the wires used in RTDs are:
a) Nickel
b) iron
c) Platinum
d) All of the above
d) All of the above
279
Electric to pneumatic transducers convert a modulaing 2210 volts DC signal to a pneumatic signal of _______to ____kPa
0 to 90
280
An electronic pressure sensor consist of a _______________ that converts pressure changes into different variables
Transmitter
281
```
Boiler fuel should be shut off immediately if it fails to ignite to
A) save power
B) prevent furnace explosions
C) prevent spills
D) prevent boiler corrosion
E) save fuel
```
B) prevent furnace explosions
282
A room thermostat should be mounted on an inside wall about ________ above the floor.
```
A) 1.25 m
B) 1.5 m
C) 0.5 m
D) 0.75 m
E) 1.0 m
```
```
verificar cual
A) 1.25 m
B) 1.5 m
C) 0.5 m
D) 0.75 m
```
283
A direct acting controller:
A) increases its output signal on a decreased input signal
B) decreases its output signal on an increased input signal
C) increases its input signal on an increased output signal
D) increases its output signal on an increased output signal
E) increases its output signal on an increased input signal
verificar cual es
D) increases its output signal on an increased output signal
E) increases its output signal on an increased input signal
284
A flame rod:
A) forms an electric circuit with the rod, flame, and relay
B) senses the temperature of the flame
C) is used for gas and oil fired burners
D) is used to light the main burner
E) forms an electric circuit with the rod, flame, and burner
E) forms an electric circuit with the rod, flame, and burner
285
All flame safeguard devices:
A) close the main fuel valve in case of pilot flame failure or main burner failure
B) are limited to temperature comfortable to the hand
C) require a photoelectric cell
D) monitor the pilot flame and main burner flame simultaneously
E) activate an alarm system if flame failure is detected
Buscar cual es la correcta
A) close the main fuel valve in case of pilot flame failure or main burner failure
B) are limited to temperature comfortable to the hand
D) monitor the pilot flame and main burner flame simultaneously
E) activate an alarm system if flame failure is detected
286
Parallel blade dampers are usually used for:
A) allowing full or no air flow
B) changing the direction of the air flow
C) varying the amount of air flow
D) mixed air control (outside and inside air)
E) proportional operation
Validar ******
| B) changing the direction of the air flow
287
A pneumatic relay can also be called a:
```
A) bleed type controller
B) selector switch
C) pneumatic-electric switch
D) cumulator
E) air reservoir
```
D) cumulator
288
An example of an auxiliary device for a pneumatic control system would be a
```
A) bellows
B) reducing valve
C) damper
D) three-way air valve
E) pump
```
Buscar cual es la respuesta ******
A) bellows
B) reducing valve
D) three-way air valve
E) pump
