BOILER LICENSE EXAM WITH VERIFIED
QUESTIONS AND ANSWERS|| ALREADY
GRADED A+|| LATEST UPDATE 2026
SECTION 1: BOILER FUNDAMENTALS & CLASSIFICATION
1. What is the primary purpose of a boiler?
A) Generate electricity
B) Produce steam or hot water for heating and power
C) Cool industrial equipment
D) Store water
Answer: B — Boilers are designed to produce steam or hot water for heating,
power generation, and industrial processes.
2. What is the maximum allowable working pressure (MAWP) for a low-
pressure steam boiler?
A) 50 psi
B) 100 psi
C) 15 psi
D) 30 psi
Answer: C — Low-pressure steam boilers are defined as operating at or below
15 psi steam pressure, as established by the ASME Boiler and Pressure Vessel
Code.
3. A hot water heating boiler is classified as low-pressure when it operates
at or below what temperature?
A) 180°F
B) 212°F
C) 250°F
D) 300°F
Answer: C — Hot water heating boilers operating at or below 250°F and 160
psi are classified as low-pressure.
4. Which term describes heat added to water that raises its temperature
without changing its phase?
A) Latent heat
,B) Sensible heat
C) Superheat
D) Vaporization
Answer: B — Sensible heat raises temperature while the water remains liquid;
latent heat is associated with phase change.
5. The amount of heat required to convert 1 lb of water at 212°F to steam
at the same temperature is called:
A) Sensible heat
B) Specific heat
C) Latent heat of vaporization
D) Superheat value
Answer: C — Latent heat of vaporization is the energy needed for phase
change at constant temperature.
6. What type of boiler uses water inside tubes and hot gases outside?
A) Fire-tube boiler
B) Water-tube boiler
C) Electric boiler
D) Condensing boiler
Answer: B — In water-tube boilers, water flows through tubes heated
externally by combustion gases.
7. Which of the following best describes a fire-tube boiler?
A) Water flows through tubes surrounded by fire and hot gases
B) Fire and hot gases pass through tubes surrounded by water
C) Steam is generated in a coil submerged in water
D) Combustion occurs outside the pressure vessel entirely
Answer: B — In a fire-tube boiler, combustion gases travel through tubes that
are immersed in water.
8. One boiler horsepower is equivalent to the evaporation of how many
pounds of water per hour from and at 212°F?
A) 24.5 lbs/hr
B) 34.5 lbs/hr
C) 44.5 lbs/hr
D) 54.5 lbs/hr
Answer: B — One boiler horsepower equals the evaporation of 34.5 pounds of
water per hour from and at 212°F.
9. The boiling point of water will _____ with an increase in pressure.
A) Not change
,B) Increase
C) Decrease
D) Increase to 212°F
Answer: B — The boiling point of water increases as pressure increases.
10. In a pressure-temperature chart, the line separating saturated steam
from superheated steam is called the:
A) Critical curve
B) Dew point line
C) Saturation curve
D) Isobaric line
Answer: C — The saturation curve denotes the temperature at which water
boils for a given pressure; beyond it steam is superheated.
11. What is the difference between a fire-tube boiler and a water-tube
boiler?
A) Fire-tube boilers have water inside tubes
B) Water-tube boilers have water inside tubes and fire outside
C) Both have the same design
D) Fire-tube boilers are always high-pressure
Answer: B — In water-tube boilers, water flows through tubes with hot gases
outside; in fire-tube boilers, hot gases pass through tubes surrounded by water.
12. What type of boiler is most commonly found in low-pressure heating
systems in commercial buildings?
A) Water-tube boiler
B) Cast iron sectional boiler
C) Coil-type boiler
D) Once-through boiler
Answer: B — Cast iron sectional boilers are widely used in low-pressure
heating applications for their durability and ease of assembly.
13. A "D" style package boiler is what type of boiler?
A) Fire-tube boiler
B) Water-tube boiler
C) Cast iron boiler
D) Electric boiler
Answer: B — A "D" style package boiler is a water-tube boiler.
14. What are the four main systems of a steam boiler?
A) Fuel, air, water, and steam systems
B) Feedwater, fuel, draft, and steam systems
, C) Combustion, feedwater, steam, and draft systems
D) Control, safety, water, and fuel systems
Answer: C — The four main systems are combustion, feedwater, steam, and
draft systems.
15. The two general types of stoker boilers are:
A) Chain grate and spreader stoker
B) Underfeed and overfeed
C) Mechanical and hand-fired
D) Pulverized and cyclone
Answer: A — Chain grate and spreader stoker are the two general types.
16. What is the normal unit for measuring boiler pressure?
A) PSI
B) Fahrenheit
C) Gallons
D) BTU
Answer: A — Pressure is commonly measured in pounds per square inch (PSI).
17. Which of the following is NOT a water-tube boiler?
A) Babcock & Wilcox
B) Stirling
C) Cornish
D) "D" type
Answer: C — Cornish boiler is a fire-tube (low-pressure) boiler, not a water-
tube boiler.
18. What is the primary purpose of a low-pressure heating boiler?
A) Generate steam above 15 psi
B) Produce electricity
C) Heat water or generate low-pressure steam for heating
D) Generate high-pressure steam for industrial processes
Answer: C — Low-pressure heating boilers are designed to heat water or
generate low-pressure steam for heating applications.
19. Anything operating above what pressure falls under high-pressure
boiler regulations?
A) 5 psig
B) 15 psig
C) 30 psig
D) 100 psig
QUESTIONS AND ANSWERS|| ALREADY
GRADED A+|| LATEST UPDATE 2026
SECTION 1: BOILER FUNDAMENTALS & CLASSIFICATION
1. What is the primary purpose of a boiler?
A) Generate electricity
B) Produce steam or hot water for heating and power
C) Cool industrial equipment
D) Store water
Answer: B — Boilers are designed to produce steam or hot water for heating,
power generation, and industrial processes.
2. What is the maximum allowable working pressure (MAWP) for a low-
pressure steam boiler?
A) 50 psi
B) 100 psi
C) 15 psi
D) 30 psi
Answer: C — Low-pressure steam boilers are defined as operating at or below
15 psi steam pressure, as established by the ASME Boiler and Pressure Vessel
Code.
3. A hot water heating boiler is classified as low-pressure when it operates
at or below what temperature?
A) 180°F
B) 212°F
C) 250°F
D) 300°F
Answer: C — Hot water heating boilers operating at or below 250°F and 160
psi are classified as low-pressure.
4. Which term describes heat added to water that raises its temperature
without changing its phase?
A) Latent heat
,B) Sensible heat
C) Superheat
D) Vaporization
Answer: B — Sensible heat raises temperature while the water remains liquid;
latent heat is associated with phase change.
5. The amount of heat required to convert 1 lb of water at 212°F to steam
at the same temperature is called:
A) Sensible heat
B) Specific heat
C) Latent heat of vaporization
D) Superheat value
Answer: C — Latent heat of vaporization is the energy needed for phase
change at constant temperature.
6. What type of boiler uses water inside tubes and hot gases outside?
A) Fire-tube boiler
B) Water-tube boiler
C) Electric boiler
D) Condensing boiler
Answer: B — In water-tube boilers, water flows through tubes heated
externally by combustion gases.
7. Which of the following best describes a fire-tube boiler?
A) Water flows through tubes surrounded by fire and hot gases
B) Fire and hot gases pass through tubes surrounded by water
C) Steam is generated in a coil submerged in water
D) Combustion occurs outside the pressure vessel entirely
Answer: B — In a fire-tube boiler, combustion gases travel through tubes that
are immersed in water.
8. One boiler horsepower is equivalent to the evaporation of how many
pounds of water per hour from and at 212°F?
A) 24.5 lbs/hr
B) 34.5 lbs/hr
C) 44.5 lbs/hr
D) 54.5 lbs/hr
Answer: B — One boiler horsepower equals the evaporation of 34.5 pounds of
water per hour from and at 212°F.
9. The boiling point of water will _____ with an increase in pressure.
A) Not change
,B) Increase
C) Decrease
D) Increase to 212°F
Answer: B — The boiling point of water increases as pressure increases.
10. In a pressure-temperature chart, the line separating saturated steam
from superheated steam is called the:
A) Critical curve
B) Dew point line
C) Saturation curve
D) Isobaric line
Answer: C — The saturation curve denotes the temperature at which water
boils for a given pressure; beyond it steam is superheated.
11. What is the difference between a fire-tube boiler and a water-tube
boiler?
A) Fire-tube boilers have water inside tubes
B) Water-tube boilers have water inside tubes and fire outside
C) Both have the same design
D) Fire-tube boilers are always high-pressure
Answer: B — In water-tube boilers, water flows through tubes with hot gases
outside; in fire-tube boilers, hot gases pass through tubes surrounded by water.
12. What type of boiler is most commonly found in low-pressure heating
systems in commercial buildings?
A) Water-tube boiler
B) Cast iron sectional boiler
C) Coil-type boiler
D) Once-through boiler
Answer: B — Cast iron sectional boilers are widely used in low-pressure
heating applications for their durability and ease of assembly.
13. A "D" style package boiler is what type of boiler?
A) Fire-tube boiler
B) Water-tube boiler
C) Cast iron boiler
D) Electric boiler
Answer: B — A "D" style package boiler is a water-tube boiler.
14. What are the four main systems of a steam boiler?
A) Fuel, air, water, and steam systems
B) Feedwater, fuel, draft, and steam systems
, C) Combustion, feedwater, steam, and draft systems
D) Control, safety, water, and fuel systems
Answer: C — The four main systems are combustion, feedwater, steam, and
draft systems.
15. The two general types of stoker boilers are:
A) Chain grate and spreader stoker
B) Underfeed and overfeed
C) Mechanical and hand-fired
D) Pulverized and cyclone
Answer: A — Chain grate and spreader stoker are the two general types.
16. What is the normal unit for measuring boiler pressure?
A) PSI
B) Fahrenheit
C) Gallons
D) BTU
Answer: A — Pressure is commonly measured in pounds per square inch (PSI).
17. Which of the following is NOT a water-tube boiler?
A) Babcock & Wilcox
B) Stirling
C) Cornish
D) "D" type
Answer: C — Cornish boiler is a fire-tube (low-pressure) boiler, not a water-
tube boiler.
18. What is the primary purpose of a low-pressure heating boiler?
A) Generate steam above 15 psi
B) Produce electricity
C) Heat water or generate low-pressure steam for heating
D) Generate high-pressure steam for industrial processes
Answer: C — Low-pressure heating boilers are designed to heat water or
generate low-pressure steam for heating applications.
19. Anything operating above what pressure falls under high-pressure
boiler regulations?
A) 5 psig
B) 15 psig
C) 30 psig
D) 100 psig
