3RD STATIONARY BOILER
ENGINEER A B TEST REAL EXAM
160 QUESTIONS AND CORRECT
VERIFIED ANSWERS LATEST AND
COMPLETE GUIDE
"A 46. What is thermal efficiency and what is considered a good percent? - CORRECT ANSWER=>
It is the ratio of heat supplied by the fuel to heat absorbed by the boiler.A good percentage is
85%, some boilers made today can reach 95%."
"A 47. How do you determine boiler capacity and what is boiler heating surfaces? - CORRECT
ANSWER=> Total heating surface determines the capacity of the boiler.Heating surface is any
surface that has hot gases on one side and boiler water on the other and is measured from the
fire side."
"B 49. What is superheated steam. Does its temperature rise"? - CORRECT ANSWER=> Steam that
has been heated to a higher temperature without raising pressure. Yes its temperature rises"
"AB 53. Define primary air, secondary air and excess air. Is secondary air necessary in a boiler
and why? - CORRECT ANSWER=> Primary air - enters the furnace with fuel and determines rate of
combustion
Secondary air - creates turbulence around fuel to complete the burning process. It is necessary
to combustion.
Excess air - is more than what is needed to complete combustion.
Yes, Secondary air is necessary, it is introduced above the fuel to burn combustible gases"
"AB 54. 3 Ts of combustion. - CORRECT ANSWER=> Time
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,Temperature
Turbulence"
"AB 55. Define PSI, PSIG and PSIA. - CORRECT ANSWER=> Pounds per square inch- pressure
exerted on a surface.
Pounds per square inch gauge- pressure that is read on a gauge.
Pounds per square inch absolute- gauge reading plus atmospheric pressure."
"AB 60. How is the density of smoke measured. How do you use a ringlemans chart? - CORRECT
ANSWER=> Measured with an opacimeter or ringlemans chart."
"AB 61. What grade of smoke are you allowed in the City of Omaha boiler operation? - CORRECT
ANSWER=> No darker than grade one, no more than five minutes per hour and no more than
three times in a twenty four hour period."
"B 62. What are seven heat losses in a boiler? - CORRECT ANSWER=> 1) Moisture in the air.2)
Moisture in the fuel.3) Moisture formed in the burning of hydrogen.4) Incomplete
combustion.5) Unburned carbon in the ash.6) heat carried away in dry flue gasses.7) Radiation
and blowdowns."
"AB 65. What is the Fyrite analyzer? Where is it used? - CORRECT ANSWER=> It is a flue gas
analyzer determine the amounts of O² and CO² in flue gases. Combustion gases are sampled
from the last pass or the breaching.It determines combustion efficiency."
"B 66. What is a Pyrometer? Where is it used? - CORRECT ANSWER=> It is thermometer for
measuring temperatures above the range of Mercury. It would be located in the hot gas
passages and in the refractory."
"B 69. Define purging and name two types. - CORRECT ANSWER=> Purging is forced removal of
combustibles from the fire-box.Pre-purge is before it is lit.Post-purge is after the combustion
cycle."
"B 73. What are some of the difficulties you may encounter when operating an oil fired plant?If
firing #4 oil and you loose pressure, what is the first two things you would look for? When
would you change a strainer? - CORRECT ANSWER=> Difficulties may include: plugged strainer,
improper venting of the tank, failure of the pumps, sludge, air in suction lines, vapor in the
pump, oil to heavy to flow, insufficient heat, faulty atomization, low oil temperature, carbon
2|Page
, formation worn burner tip, or low oil pressure.The first two things to look for are plugged
strainer or pump failure.You would valve over to a clean strainer if the delta-P was excessive."
"B 74. Name three types of nozzles used in oil burners.Explain where secondary air is admitted.
- CORRECT ANSWER=> Rotary atomizing, steam atomizing, air atomizing, and pressure
atomizing.Secondary air is admitted around the tip."
"B 75. Under what conditions must fuel oil be heated, how is it heated, and how hot is heated? -
CORRECT ANSWER=> #4, #5, #6 oils need to be heated.Heated using steam or electricity.oil
should not be heated to more than 10°F below its flash point.#4 = 135° F, #5 = 185° F, #6 = 220°
F"
"A 80. Name five electrical devices used on a boiler. - CORRECT ANSWER=> Low water alarm.
Induced or forced draft fans, oil pumps. flame controls. damper motors. flow switch. water level
control lights.CC TV cameras"
"AB 81. What is natural draft? What causes natural draft? - CORRECT ANSWER=> When the
weight of the warm air in the stack is less than the cool air around the stack it causes an upward
flow pulling air through the furnace.The heavier, cool air outside the stack gives a push to the
warm lighter air in the stack causing air to flow through the furnace."
"B 82. How is the flow of natural draft controlled? - CORRECT ANSWER=> By dampers mounted in
the breeching and/or the burner operated by automatic controls either electric or pneumatic."
"A 84. How is draft measured? What is draft gauge used for and how is it installed? - CORRECT
ANSWER=> In inches of water with a manometer or a "U" gauge.A draft gauge is used to
measure the pressure difference of the boiler room and inside the the setting or firebox.One
tube is connected into the breeching and the other end is open to the boiler room (or
atmosphere). Pressure moves the liquids in the tube. The difference is read in tenths of an
inch."
"B 85. When would you employ forced draft? - CORRECT ANSWER=> When you fail to have
sufficient natural draft through the boiler."
"AB 86. What is mechanical draft? Name and describe three types. - CORRECT ANSWER=> The
adding of fans to make up for insufficient natural draft. Induced-is a fan in the breeching
between the boiler and the stack pulling air through the furnace. The boiler operates below
atmospheric pressure. Forced-is a fan at the point of air entry pushing air through the furnace.
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ENGINEER A B TEST REAL EXAM
160 QUESTIONS AND CORRECT
VERIFIED ANSWERS LATEST AND
COMPLETE GUIDE
"A 46. What is thermal efficiency and what is considered a good percent? - CORRECT ANSWER=>
It is the ratio of heat supplied by the fuel to heat absorbed by the boiler.A good percentage is
85%, some boilers made today can reach 95%."
"A 47. How do you determine boiler capacity and what is boiler heating surfaces? - CORRECT
ANSWER=> Total heating surface determines the capacity of the boiler.Heating surface is any
surface that has hot gases on one side and boiler water on the other and is measured from the
fire side."
"B 49. What is superheated steam. Does its temperature rise"? - CORRECT ANSWER=> Steam that
has been heated to a higher temperature without raising pressure. Yes its temperature rises"
"AB 53. Define primary air, secondary air and excess air. Is secondary air necessary in a boiler
and why? - CORRECT ANSWER=> Primary air - enters the furnace with fuel and determines rate of
combustion
Secondary air - creates turbulence around fuel to complete the burning process. It is necessary
to combustion.
Excess air - is more than what is needed to complete combustion.
Yes, Secondary air is necessary, it is introduced above the fuel to burn combustible gases"
"AB 54. 3 Ts of combustion. - CORRECT ANSWER=> Time
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,Temperature
Turbulence"
"AB 55. Define PSI, PSIG and PSIA. - CORRECT ANSWER=> Pounds per square inch- pressure
exerted on a surface.
Pounds per square inch gauge- pressure that is read on a gauge.
Pounds per square inch absolute- gauge reading plus atmospheric pressure."
"AB 60. How is the density of smoke measured. How do you use a ringlemans chart? - CORRECT
ANSWER=> Measured with an opacimeter or ringlemans chart."
"AB 61. What grade of smoke are you allowed in the City of Omaha boiler operation? - CORRECT
ANSWER=> No darker than grade one, no more than five minutes per hour and no more than
three times in a twenty four hour period."
"B 62. What are seven heat losses in a boiler? - CORRECT ANSWER=> 1) Moisture in the air.2)
Moisture in the fuel.3) Moisture formed in the burning of hydrogen.4) Incomplete
combustion.5) Unburned carbon in the ash.6) heat carried away in dry flue gasses.7) Radiation
and blowdowns."
"AB 65. What is the Fyrite analyzer? Where is it used? - CORRECT ANSWER=> It is a flue gas
analyzer determine the amounts of O² and CO² in flue gases. Combustion gases are sampled
from the last pass or the breaching.It determines combustion efficiency."
"B 66. What is a Pyrometer? Where is it used? - CORRECT ANSWER=> It is thermometer for
measuring temperatures above the range of Mercury. It would be located in the hot gas
passages and in the refractory."
"B 69. Define purging and name two types. - CORRECT ANSWER=> Purging is forced removal of
combustibles from the fire-box.Pre-purge is before it is lit.Post-purge is after the combustion
cycle."
"B 73. What are some of the difficulties you may encounter when operating an oil fired plant?If
firing #4 oil and you loose pressure, what is the first two things you would look for? When
would you change a strainer? - CORRECT ANSWER=> Difficulties may include: plugged strainer,
improper venting of the tank, failure of the pumps, sludge, air in suction lines, vapor in the
pump, oil to heavy to flow, insufficient heat, faulty atomization, low oil temperature, carbon
2|Page
, formation worn burner tip, or low oil pressure.The first two things to look for are plugged
strainer or pump failure.You would valve over to a clean strainer if the delta-P was excessive."
"B 74. Name three types of nozzles used in oil burners.Explain where secondary air is admitted.
- CORRECT ANSWER=> Rotary atomizing, steam atomizing, air atomizing, and pressure
atomizing.Secondary air is admitted around the tip."
"B 75. Under what conditions must fuel oil be heated, how is it heated, and how hot is heated? -
CORRECT ANSWER=> #4, #5, #6 oils need to be heated.Heated using steam or electricity.oil
should not be heated to more than 10°F below its flash point.#4 = 135° F, #5 = 185° F, #6 = 220°
F"
"A 80. Name five electrical devices used on a boiler. - CORRECT ANSWER=> Low water alarm.
Induced or forced draft fans, oil pumps. flame controls. damper motors. flow switch. water level
control lights.CC TV cameras"
"AB 81. What is natural draft? What causes natural draft? - CORRECT ANSWER=> When the
weight of the warm air in the stack is less than the cool air around the stack it causes an upward
flow pulling air through the furnace.The heavier, cool air outside the stack gives a push to the
warm lighter air in the stack causing air to flow through the furnace."
"B 82. How is the flow of natural draft controlled? - CORRECT ANSWER=> By dampers mounted in
the breeching and/or the burner operated by automatic controls either electric or pneumatic."
"A 84. How is draft measured? What is draft gauge used for and how is it installed? - CORRECT
ANSWER=> In inches of water with a manometer or a "U" gauge.A draft gauge is used to
measure the pressure difference of the boiler room and inside the the setting or firebox.One
tube is connected into the breeching and the other end is open to the boiler room (or
atmosphere). Pressure moves the liquids in the tube. The difference is read in tenths of an
inch."
"B 85. When would you employ forced draft? - CORRECT ANSWER=> When you fail to have
sufficient natural draft through the boiler."
"AB 86. What is mechanical draft? Name and describe three types. - CORRECT ANSWER=> The
adding of fans to make up for insufficient natural draft. Induced-is a fan in the breeching
between the boiler and the stack pulling air through the furnace. The boiler operates below
atmospheric pressure. Forced-is a fan at the point of air entry pushing air through the furnace.
3|Page
