MN BOILER LICENSE EXAM 2025
QUESTIONS AND ANSWERS
what are the conditions necessary for good combustion?
a) low sulfur content
b) Thermal, thermocoupler, tubular
c) turbulence, temperature, time 3T's - ANS c) turbulence, temperature, time 3T's
why is secondary air necessary in hand fired boilers?
a) Necessary to burn the combustible gases
b) if primary air should fail
c) used only if sulfur content is high - ANS a) Necessary to burn the combustible gases
when pressure increases on steam from a given amount of water what happens to its volume
and latent heat?
a) increases
b) decreases
c) remains the same - ANS b) decreases
when pressure increases on steam from a given amount of water what happens to its
temperature?
a) increases
b) decreases
c) remains the same - ANS a) increases
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,when carbon monoxide (co) is formed and carbon dioxide (co2) is very high what does it
generally signify?
a) More "under the fire air" is needed
b) less "under the fire air" is required
c) more "over the fire" air is needed
d) less "over the fire" is needed less - ANS c) more "over the fire" air is needed
excess air is an expression that refers to:
a) overabundance of air
b) theoretical amount of air
c) air supplied above that theoretically required - ANS c) air supplied above that theoretically
required
a good percentage of carbon dioxide when burning oil is:
a) 12%
b) 8 %
c) 10% - ANS a) 12%
what is draft on a boiler in operation?
a) Flow of gases through boiler
b) difference in pressure between atmosphere and furnace or firebox
c) difference between atmospheric pressure and breeching - ANS b) difference in pressure
between atmosphere and furnace or firebox
which has greater heating value per pound?
a) oil
b) coal - ANS a) oil (18000 - 19500 BTU)
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,(coal has (6900 - 12910 BTU))
heavy oil must be heated before entering the burner to:
a) increase carbon content
b) decreased sulfur content
c) get proper atomization - ANS c) get proper atomization
why should a daily log be kept of flue gas temperature?
a) Valuable information in case of explosion
b) superintendent files them
c) change an operation, causing heat loss, can be detected - ANS c) change an operation,
causing heat loss, can be detected
find SWP of a boiler 72 inches in diameter, thickness of one-half inch, tensile strength of 55,000
pounds, quadruple riveted butt and strap joint (.94) factor of safety 5:
a) 14.3
b) 143.6
c) 1436 - ANS b) 143.6
the total heat of steam is 1,188 BTUs, and feed water temperature is 182 degrees Fahrenheit.
What is the factor of evaporation?
a) 107
b) 10.7
c) 1.07 - ANS c) 1.07
why would viscosity be important in fuel oil?
a) more heat is recovered in water
b) has more volatile hydrocarbons
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, c) affects ease with which it can be handled - ANS c) effects ease with which it can be
handled
why is too much air objectionable?
a) Cost too high
b) loss of efficiency
c) corrosive effect - ANS b) loss of efficiency
what is a fyrite used for?
a) flue gas analyzer
b) combustion programmer
c) water analysis - ANS a) flue gas analyzer
absolute pressure is (ABS):
a) atmospheric pressure - gauge pressure
b) gauge pressure minus atmospheric pressure
c) atmospheric pressure + gauge pressure - ANS c) atmospheric pressure + gauge pressure
when pressure of steam increases, what happens to the temperature?
a) Goes up
b) goes down
c) remains the same - ANS a) Goes up
find the square feet of heating surface of a flu 4" in diameter and 20' in length:
a) 25'sq
b) 251.32'sq
c) 2513'sq
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QUESTIONS AND ANSWERS
what are the conditions necessary for good combustion?
a) low sulfur content
b) Thermal, thermocoupler, tubular
c) turbulence, temperature, time 3T's - ANS c) turbulence, temperature, time 3T's
why is secondary air necessary in hand fired boilers?
a) Necessary to burn the combustible gases
b) if primary air should fail
c) used only if sulfur content is high - ANS a) Necessary to burn the combustible gases
when pressure increases on steam from a given amount of water what happens to its volume
and latent heat?
a) increases
b) decreases
c) remains the same - ANS b) decreases
when pressure increases on steam from a given amount of water what happens to its
temperature?
a) increases
b) decreases
c) remains the same - ANS a) increases
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,when carbon monoxide (co) is formed and carbon dioxide (co2) is very high what does it
generally signify?
a) More "under the fire air" is needed
b) less "under the fire air" is required
c) more "over the fire" air is needed
d) less "over the fire" is needed less - ANS c) more "over the fire" air is needed
excess air is an expression that refers to:
a) overabundance of air
b) theoretical amount of air
c) air supplied above that theoretically required - ANS c) air supplied above that theoretically
required
a good percentage of carbon dioxide when burning oil is:
a) 12%
b) 8 %
c) 10% - ANS a) 12%
what is draft on a boiler in operation?
a) Flow of gases through boiler
b) difference in pressure between atmosphere and furnace or firebox
c) difference between atmospheric pressure and breeching - ANS b) difference in pressure
between atmosphere and furnace or firebox
which has greater heating value per pound?
a) oil
b) coal - ANS a) oil (18000 - 19500 BTU)
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,(coal has (6900 - 12910 BTU))
heavy oil must be heated before entering the burner to:
a) increase carbon content
b) decreased sulfur content
c) get proper atomization - ANS c) get proper atomization
why should a daily log be kept of flue gas temperature?
a) Valuable information in case of explosion
b) superintendent files them
c) change an operation, causing heat loss, can be detected - ANS c) change an operation,
causing heat loss, can be detected
find SWP of a boiler 72 inches in diameter, thickness of one-half inch, tensile strength of 55,000
pounds, quadruple riveted butt and strap joint (.94) factor of safety 5:
a) 14.3
b) 143.6
c) 1436 - ANS b) 143.6
the total heat of steam is 1,188 BTUs, and feed water temperature is 182 degrees Fahrenheit.
What is the factor of evaporation?
a) 107
b) 10.7
c) 1.07 - ANS c) 1.07
why would viscosity be important in fuel oil?
a) more heat is recovered in water
b) has more volatile hydrocarbons
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, c) affects ease with which it can be handled - ANS c) effects ease with which it can be
handled
why is too much air objectionable?
a) Cost too high
b) loss of efficiency
c) corrosive effect - ANS b) loss of efficiency
what is a fyrite used for?
a) flue gas analyzer
b) combustion programmer
c) water analysis - ANS a) flue gas analyzer
absolute pressure is (ABS):
a) atmospheric pressure - gauge pressure
b) gauge pressure minus atmospheric pressure
c) atmospheric pressure + gauge pressure - ANS c) atmospheric pressure + gauge pressure
when pressure of steam increases, what happens to the temperature?
a) Goes up
b) goes down
c) remains the same - ANS a) Goes up
find the square feet of heating surface of a flu 4" in diameter and 20' in length:
a) 25'sq
b) 251.32'sq
c) 2513'sq
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