Unit 3 Boiler Safety Devices Flashcards

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1
Q

When the energy output and the energy demand are equal, the boiler pressure

Select one:

a. becomes unstable
b. rises
c. falls
d. remains constant

A

d. remains constant

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2
Q
An important fitting, which is installed between a steam boiler pressure gauge and the boiler itself and is designed to prevent damage to the gauge, is a:
Select one:
a. Tee with a plug
b. Syphon 
c. Blowdown valve
d. Test connection for an inspector
A

b. Syphon

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3
Q

Primary controls, as used in a burner management system:
Select one:
a. Should be cleaned of carbon deposits monthly.
b. Generate a voltage, which is then used to monitor flames.
c. must shut off the fuel within four seconds of flame failure.
d. Are unreliable and unsafe.

A

c. must shut off the fuel within four seconds of flame failure.

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4
Q

All boiler fittings not properly or clearly identified:
Select one:
a. Must not be used
b. May be used for low pressure services
c. Are acceptable for some powerhouse piping applications.
d. Must be sent back to the manufacturer for proper identification.

A

a. Must not be used

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5
Q

Testing a safety valve on a boiler by pulling the try-lever
Select one:
a. Ensures the popping pressure is correct
b. Ensures the closing pressure is correct
c. Takes approximately two seconds
d. Ensures the valve is free to operate

A

d. Ensures the valve is free to operate

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6
Q

In hot water boiler firing rate control systems, the measured variable is

Select one:

a. the inlet water temperature
b. the outlet water pressure
c. the combustion air pressure
d. the outlet water temperature

A

d. the outlet water temperature

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7
Q

Tubular gauge glasses:
Select one:
a. Are suitable for pressures up to about 3000 kPa
b. Are made of glass, in order to resistant boiler alkalinity
c. Indicate the level more accurately than other forms of water level indication
d. Can only be installed on low-pressure boilers

A

a. Are suitable for pressures up to about 3000 kPa

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8
Q

Every steam boiler must have a safety valve that is:
Select one:
a. Placed in the piping system leading from the steam stop valve.
b. Fitted securely to a shut-off valve, which is directly connected to the top of the boiler.
c. Fitted in a vertical position, directly connected to the top of the boiler.
d. Connected to the steam or water space of the boiler, without any intervening fitting.

A

c. Fitted in a vertical position, directly connected to the top of the boiler.

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9
Q
An outside screw and yoke valve: 
Select one:
a. Must be a gate valve 
b. Shows its operating position  
c. Is difficult to lubricate 
d. Requires no packing
A

b. Shows its operating position

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10
Q
The popping pressure of a safety valve \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ without replacing its spring:
Select one:
a. Cannot be changed
b. Can only be increased by 5%
c. Can only be decreased by 5%
d. Can be changed by plus or minus 5%
A

d. Can be changed by plus or minus 5%

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11
Q

A safety relief valve is similar to a safety valve except that it:
Select one:
a. Does not have a blowdown ring or bottom guides
b. Must have greater blowdown
c. May have an isolation valve placed between it and the pressure vessel
d. Must discharge directly to the atmosphere

A

a. Does not have a blowdown ring or bottom guides

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12
Q

When an automatic unattended boiler starts up, the programming control will first:
Select one:
a. Energize the ignition transformer and pilot gas solenoid valve
b. Start the post purge period
c. Start the forced draft fan
d. Energize the main gas valve

A

c. Start the forced draft fan

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13
Q
What is responsible for the “popping action” of a safety valve?
Select one:
a. Amount of spring compression
b. Blow down ring adjustment
c. A lip on the valve disc 
d. Temperature of the steam
A

c. A lip on the valve disc

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14
Q

A low water fuel cutoff on an unattended steam boiler shall be installed so that
Select one:
a. It cannot be rendered inoperative
b. It starts the feed water pump
c. It can be isolated if it is not required
d. It shuts down the burner when the water level falls below the lowest visible part of the gauge glass.

A

a. It cannot be rendered inoperative

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15
Q
How many blow-off valves are required by most power boilers?
Select one:
a. Zero 
b. One  
c. Two 
d. Three
A

c. Two

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16
Q

What is the purpose of the high limit control on a hot water boiler?
Select one:
a. To stop the boiler if the water level control fails.
b. To act as a emergency stop for the operator
c. To shut down the burner if the water temperature exceeds 121 degrees Celsius.
d. To prevent the boiler pressure from rising above 1100 kPa gauge.

A

c. To shut down the burner if the water temperature exceeds 121 degrees Celsius.

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17
Q

After extinguishing the main flame, the next step in a programmed burner shutdown is
Select one:
a. The timer motor stops
b. A post-purge begins.
c. Operation control switch contacts close
d. Flame failure switch contacts open

A

b. A post-purge begins.

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18
Q
The type of firing rate control frequently used on small capacity packaged boilers is:
Select one:
a. a modulating control
b. a high fuel pressure cut-off
c. a constant pressure control
d. an on/off control
A

d. an on/off control

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19
Q

When is a stop valve allowed between a heating boiler’s safety valve and the boiler drum?
Select one:
a. Only if the stop valve is locked open
b. If there is more than one safety valve
c. Never
d. If the stop valve is the quick opening design

A

c. Never

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20
Q

If a boiler produces steam at a higher rate than the rate of steam consumption, and this condition goes unchecked

Select one:

a. soot will develop on the fireside
b. the boiler efficiency will drop
c. the boiler will over-pressurize
d. the boiler will overheat

A

c. the boiler will over-pressurize

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21
Q
A boiler with a single safety valve has a maximum allowable working pressure of 1000 kPa. What is the maximum boiler pressure permissible when the safety valve is blowing? 
Select one:
a. 1060 kPa 
b. 1000 kPa
c. 1030 kPa
d. 1100 kPa
A

a. 1060 kPa

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22
Q
What does the boiler inspector do to prevent tampering with the settings of a safety valve?
Select one:
a. Installs a gag
b. Installs a seal 
c. Plugs the adjusting hole
d. Covers the valve
A

b. Installs a seal

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23
Q

Flat glass water gauges are often used because:
Select one:
a. It is easier to see the level
b. A light can be installed behind them
c. They are more compact
d. They can withstand higher pressures than tubular gauge glasses

A

d. They can withstand higher pressures than tubular gauge glasses

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24
Q

An automatic boiler on-off firing rate control has one adjustment for pressure set-point and another for:
Select one:
a. Differential adjustment
b. Manual or automatic control
c. Water level adjustment
d. High steam pressure limit set point adjustment.

A

a. Differential adjustment

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25
Q

A feedwater pipe, where connected to a power boiler, must have:
Select one:
a. A check valve, with a stop valve between the check valve and the boiler
b. A check valve between the stop valve and the boiler
c. A stop valve only
d. A quick and slow opening stop valve

A

a. A check valve, with a stop valve between the check valve and the boiler

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26
Q

When used on a boiler, modulating combustion control will:
Select one:
a. Change air and fuel flow proportionally to changes in steam pressure
b. Always be at set point when demand is at 50%
c. Alter only the air flow if a selector station is on manual
d. Respond to changes in atmospheric pressure

A

a. Change air and fuel flow proportionally to changes in steam pressure

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27
Q

A packaged steam boiler modulating combustion control system will routinely:
Select one:
a. Maintain drum level within a desired range
b. Maintain flue gas temperature at some set point
c. Maintain boiler steam pressure within a desired range
d. Alter flue flow without changing the air flow

A

c. Maintain boiler steam pressure within a desired range

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28
Q

If a high pressure boiler is on high fire with the main steam stop valve closed, the safety valves must ensure that the:
Select one:
a. Boiler pressure does not exceed the maximum allowable working pressure of the boiler by more than 6%.
b. Boiler pressure does not exceed the set point of the safety valve.
c. Steam pressure does not exceed the maximum allowable working pressure of the boiler.
d. Boiler pressure does not exceed the hydrostatic test pressure.

A

a. Boiler pressure does not exceed the maximum allowable working pressure of the boiler by more than 6%.

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29
Q

The lowest visible point of the gauge glass for a horizontal firetube power boiler with diameter greater than 400 mm must be:
Select one:
a. Level with the highest fire tube
b. Level with the normal water level
c. 25 mm below the highest fire tube
d. 75 mm above the lowest permissible water level

A

d. 75 mm above the lowest permissible water level

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30
Q

When starting up a cold boiler with a fully modulating firing rate control, it must be

Select one:

a. limited to low-fire until the boiler is sufficiently warm.
b. kept on manual high-fire, to reduce flue gas condensation losses.
c. placed on manual high-fire to raise the boiler temperature or pressure as fast as possible.
d. kept on automatic, to prevent thermal shock.

A

a. limited to low-fire until the boiler is sufficiently warm.

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31
Q
The prime importance of boiler fittings is:
Select one:
a. Economics
b. To satisfy regulations 
c. Safety & efficiency
d. Convenience
A

c. Safety & efficiency

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32
Q

A high gas pressure fuel cut-off switch:
Select one:
a. Closes when gas pressure is too high
b. Automatically resets itself when the gas pressure is restored
c. Is located upstream of the automatic fuel valve
d. Prevents excessive fuel pressure from creating an unstable flame condition

A

d. Prevents excessive fuel pressure from creating an unstable flame condition

33
Q
According to ASME IV, the scale of a pressure gauge for a steam boiler shall be graduated to not less than
Select one:
a. 100 to 300 kPa
b. 200 to 414 kPa 
c. 2500 to 3000 kPa
d. 125 to 325 kPa
A

b. 200 to 414 kPa

34
Q

The thermal element of a hot water boiler limit control:
Select one:
a. Measures pressure
b. Senses temperature, and changes it to a corresponding pressure
c. Must use a capillary tube
d. Measures the enthalpy of the boiler water

A

b. Senses temperature, and changes it to a corresponding pressure

35
Q

A modulating control steam heating boiler:
Select one:
a. Is always fully automatic
b. Will have a narrow operating pressure range
c. Maintains a steadier boiler pressure than multi-position control
d. Will have a constant combustion air flow rate

A

c. Maintains a steadier boiler pressure than multi-position control

36
Q

A manual “high-low” switch should be switched to “high” or “auto”:
Select one:
a. Prior to ignition of the main flame
b. When pressure is too low
c. When the boiler has been properly warmed up
d. During boiler pre-purge

A

c. When the boiler has been properly warmed up

37
Q
A high pressure boiler with a heating surface not exceeding \_\_\_\_\_\_\_\_\_ in area can have only a single safety valve. 
Select one:
a. 47 m2 
b. 36 m2
c. 28 m2
d. 19 m2
A

a. 47 m2

38
Q
Prior to a boiler safety valve popping during routine boiler operation:
Select one:
a. A try lever test should be performed 
b. The pressure gage should be checked
c. The high pressure cut-off should open
d. The high level alarm should sound
A

c. The high pressure cut-off should open

39
Q

The water level indicated in a boiler gauge glass is:
Select one:
a. Slightly less than the actual drum level.
b. The actual drum level, regardless of operating conditions
c. Slightly higher than the actual drum level when the pressure is high.
d. Slightly higher than the actual drum level when the boiler is on low fire.

A

a. Slightly less than the actual drum level.

40
Q

If a boiler’s safety valves have insufficient relief capacity, the boiler pressure may:
Select one:
a. Not rise more than 15% above the MAWP
b. Remain at the MAWP
c. Force water from the boiler, causing a low water condition.
d. Rise more than 6% above the MAWP.

A

d. Rise more than 6% above the MAWP.

41
Q

The set pressure of a safety valve may only be adjusted by:
Select one:
a. a power engineer
b. authorized and certified personnel
c. the safety valve manufacturer, its authorized representative, or an assembler
d. an industrial insurance adjuster

A

c. the safety valve manufacturer, its authorized representative, or an assembler

42
Q
To increase the opening pressure of a safety valve,:
Select one:
a. Raise the blowdown ring
b. Increase spring compression 
c. Reduce spring compression
d. Lower the blowdown ring
A

b. Increase spring compression

43
Q

A hot water boiler operating control (Aquastat) may be a pressure switch:
Select one:
a. that is normally open
b. that responds to the expansion and contraction of boiler water
c. operated by a filled system thermometer
d. that is sensitive to steam pressure

A

c. operated by a filled system thermometer

44
Q

Thermocouples are connected in series to:
Select one:
a. Monitor more than one flame source
b. Increase the sensitivity of the detection system
c. Generate a higher voltage
d. Provide redundancy if one should fail

A

c. Generate a higher voltage

45
Q

When the energy output and the energy demand are equal, the water temperature of a hot water boiler

Select one:

a. remains constant
b. rises
c. becomes unstable
d. falls

A

a. remains constant

46
Q

When a differential pressure is used to measure water level in a boiler steam drum, the connection to the steam space:
Select one:
a. Forms the variable leg of the level indicator
b. Maintains a constant steam pressure signal to the head meter
c. Is connected to the low pressure side of the level indicator
d. Forms the constant head of the level indicator

A

d. Forms the constant head of the level indicator

Fig 24. page 3-31

47
Q

The programmer will go through a post purge:
Select one:
a. Only if pilot fails to ignite
b. Only on flame failure
c. By manually advancing the timer
d. On any type of shutdown except power outage

A

d. On any type of shutdown except power outage

48
Q
A photoelectric flame scanner:
Select one:
a. uses a pilot-stat
b. conducts current through the flame
c. Requires a clear line of sight to the flame 
d. Produces a steady voltage signal
A

c. Requires a clear line of sight to the flame

49
Q
The blowdown on a safety valve is adjusted by turning the:
Select one:
a. Valve disc 
b. Adjusting nut 
c. Adjusting ring  
d. Valve seat
A

c. Adjusting ring

50
Q
The safety valves on a boiler are set to open at 1380 kPa. The boiler MAWP is 1380 kPa. How much higher can the boiler pressure rise above 1380 kPa, if it is fired at full capacity with the steam outlet valve closed?
Select one:
a. 37.5 kPa
b. 41.4 kPa
c. 0 kPa
d. 82.8 kPa
A

d. 82.8 kPa

51
Q

In steam boiler firing rate control systems, the measured variable is

Select one:

a. the steam pressure
b. fuel pressure
c. firing rate control valve position
d. combustion air damper position

A

a. the steam pressure

52
Q

Do not open the safety valve with the test lever:
Select one:
a. If the valve is less than 2.5 cm inlet diameter
b. If the pressure is less than 75% working pressure
c. If there are more than two safety valves on the boiler
d. If the valve is not vented to the roof

A

b. If the pressure is less than 75% working pressure

53
Q
At the end of the pre-purge period, the programming control:
Select one:
a. Opens the main fuel valve
b. Closes the pilot valve
c. Ends the ignition trial
d. Energizes the ignition transformer
A

d. Energizes the ignition transformer

54
Q

One purpose of the small valve on top of the shell of most boilers, which is not required by code, is to:
Select one:
a. allow water into the boiler when the boiler is being drained or cooled preventing the formation of a vacuum.
b. allow water to escape before the steam stop valve is opened during the warm-up period.
c. allow air to escape from the boiler when the boiler is being filled with water.
d. allow air into the boiler when the boiler is being filled with water.

A

c. allow air to escape from the boiler when the boiler is being filled with water.

55
Q
Combustion air safety switches are found:
Select one:
a. On natural draft boilers
b. On boilers that use mechanical draft 
c. On light oil-fired boilers
d. On gas fired boilers
A

b. On boilers that use mechanical draft

56
Q
Transparent gauge glasses are lined with mica to:
Select one:
a. Protect the glass 
b. Cool the glass
c. Increase the strength of the glass
d. Provide a high temperature seal
A

a. Protect the glass

57
Q

The purpose of the spring in a safety valve is to:
Select one:
a. Help open the testing lever
b. Adjust the pressure setting of the valve
c. Adjust the blow down of the valve
d. Hold down the disc on the seat

A

d. Hold down the disc on the seat

58
Q

When installing a gauge siphon, it is important to:
Select one:
a. Keep the siphon dry
b. Install it downstream of an inspector’s test connection
c. First fill it with water
d. Install it as close to the boiler as possible

A

c. First fill it with water

59
Q
What is the minimum number of safety valves required on a boiler that has a heating surface of 42 m2?
Select one:
a. None
b. One 
c. Two
d. Three
A

b. One

60
Q
An essential fitting between the boiler and the steam pressure gauge is a:
Select one:
a. Check valve
b. Gate valve
c. Gauge glass
d. Siphon
A

d. Siphon

61
Q
The main controlling device used with an On/Off combustion fuel control is a \_\_\_\_\_ sensing element.
Select one:
a. Pressure 
b. Level
c. Flow
d. Electronic
A

a. Pressure

62
Q

When boilers cycle on and off frequently

Select one:

a. their efficiency drops.
b. they should be kept on manual high fire to prevent excessive cycling.
c. automatic firing rate controls should be used.
d. they do not require post-purges.

A

a. their efficiency drops.

63
Q

A blowdown ring is used on a safety valve to:
Select one:
a. Adjust the operating pressure of the valve
b. Prevent the safety valve from popping while blowing down the boiler
c. Increase the blowdown frequency of the safety valve
d. Adjust the differential between opening and closing pressures

A

d. Adjust the differential between opening and closing pressures

64
Q
A photoelectric flame scanner:
Select one:
a. uses a pilot-stat
b. conducts current through the flame 
c. Requires a clear line of sight to the flame
d. Produces a steady voltage signal
A

c. Requires a clear line of sight to the flame

65
Q
A mercury switch bulb is under high vacuum and contains inert gas: 
Select one:
a. So it will not explode 
b. To keep the mercury from oxidizing 
c. To decrease electrical resistance  
d. So the contacts will not overheat
A

b. To keep the mercury from oxidizing

66
Q

In the firing rate control systems for steam and hot water boilers, the final control elements manipulate

Select one:

a. the fuel flow and the stack temperature.
b. the steam pressure and the water temperature.
c. the fuel pressure and the combustion air pressure.
d. the fuel flow and the airflow.

A

d. the fuel flow and the airflow.

67
Q
The purpose of the tee fitting on the piping leading to a boiler steam pressure gauge is to:
Select one:
a. Bypass the siphon tube
b. Test a sample of steam for purity
c. Attach a test gauge 
d. Blowoff condensate from the pigtail
A

c. Attach a test gauge

68
Q

A variable resistance modulating control:
Select one:
a. Works in conjunction with a modulating motor
b. Utilizes a mercury switch
c. Senses steam temperature
d. Operates only in the vertical position

A

a. Works in conjunction with a modulating motor

69
Q

During the start-up of a fully automatic boiler, the main burner safety shut-off valve (SSOV):
Select one:
a. Must be opened before the ignition transformer energizes
b. Can be opened any time during the start-up sequence
c. Should be opened as soon as the pilot valve opens
d. Must be closed before pilot ignition

A

d. Must be closed before pilot ignition

70
Q

An operator should check that a boiler safety valve will open at its set pressure by:
Select one:
a. Asking the inspector to bring a master pressure gauge
b. Increasing the boiler pressure and noting the pressure at which the valve opens
c. Putting a piece of pipe over the lifting lever and lifting the valve off its seat when the set pressure is reached
d. Using air pressure during a shutdown to raise the pressure in the boiler until the set pressure is reached

A

b. Increasing the boiler pressure and noting the pressure at which the valve opens

71
Q

A test connection for a boiler pressure gauge:
Select one:
a. Should be located upstream of a siphon
b. Should be of 12.7 mm NPT size
c. Is required on all boilers
d. Is usually installed between the siphon and the pressure gauge

A

d. Is usually installed between the siphon and the pressure gauge

72
Q
A thermocouple:
Select one:
a. Consists of two similar wires
b. Produces an electric signal 
c. Senses infrared light from the flame
d. Is made of several thermopiles connected in series
A

b. Produces an electric signal

73
Q

Safety valves “pop” open because the steam pressure:
Select one:
a. Acts upon a blow down ring
b. Acts upon a huddling chamber
c. Acts upon a larger area as soon as the valve opens
d. Increases due to the discharge ports

A

c. Acts upon a larger area as soon as the valve opens

74
Q

The discharge pipe from a boiler safety valve is supported independently of the safety valve:
Select one:
a. Because the steam drum cannot support the extra mass of the discharge pipe
b. So the discharge pipe can drain more easily
c. So the discharge pipe can expand without putting force on the safety valve
d. To prevent leakage at the pipe joint

A

c. So the discharge pipe can expand without putting force on the safety valve

75
Q
A float operated low water fuel cutoff has its switch separated from boiler pressure by:
Select one:
a. A float cage
b. A seal cage
c. A bellows 
d. Packing
A

c. A bellows

76
Q
The purpose of the pipe siphon installed between the boiler and the pressure gauge is to prevent:
Select one:
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
A

c. Hot steam from entering the gauge

77
Q

A flame rod:
Select one:
a. Is used in combination with a photocell
b. Is used only for oil fired burners
c. Forms an electric circuit with the rod, flame and burner
d. Develops a high resistance in the presence of a flame.

A

c. Forms an electric circuit with the rod, flame and burner

78
Q

In steam boiler firing rate control systems, the measured variable is

Select one:

a. the steam pressure
b. fuel pressure
c. combustion air damper position
d. firing rate control valve position

A

a. the steam pressure

79
Q

A low fire start switch:
Select one:
a. Is a type of manual over ride
b. Ensures the purge takes place with the damper in the low-fire position
c. Acts as a pre-ignition interlock to ensure minimum damper setting during ignition
d. Is closed when the damper is at high fire.

A

c. Acts as a pre-ignition interlock to ensure minimum damper setting during ignition