First Class Steam License Practice Exam, with answers and
rationales 2026/2027 version /instant pdf
1. A boiler safety valve is primarily designed to:
A. Prevent excessive boiler pressure
B. Maintain constant water level
C. Control fuel temperature
D. Remove dissolved solids
Answer: A
Rationale: The safety valve automatically relieves pressure when the boiler reaches its set
pressure.
2. If boiler pressure rises above the normal operating range, the operator should first:
A. Follow the established operating procedure and determine the cause
B. Disable the safety valve
C. Increase firing rate
D. Close all safety devices
Answer: A
Rationale: Abnormal pressure requires immediate assessment and corrective action within
approved procedures.
3. What is the principal purpose of a deaerator?
A. Remove dissolved oxygen and other gases from feedwater
B. Increase dissolved oxygen
C. Remove steam from the boiler
D. Increase boiler pressure
Answer: A
Rationale: Dissolved oxygen can cause serious corrosion, particularly pitting, so deaeration
protects the feedwater system.
4. A boiler with excessive scale will generally have:
A. Reduced heat transfer and increased metal temperature
B. Improved efficiency
C. Lower fuel consumption
D. Better circulation
Answer: A
Rationale: Scale acts as an insulating layer, reducing heat transfer and potentially overheating
boiler metal.
5. What is the primary purpose of an economizer?
A. Recover flue-gas heat to preheat feedwater
B. Cool combustion gases
,C. Remove boiler sludge
D. Reduce feedwater temperature
Answer: A
Rationale: An economizer improves efficiency by recovering waste heat.
6. Superheated steam is steam that:
A. Has been heated above its saturation temperature at a given pressure
B. Contains large amounts of liquid water
C. Is below atmospheric pressure
D. Has been completely condensed
Answer: A
Rationale: Superheating adds sensible heat after the steam has reached saturation.
7. What is the primary danger of firing a boiler with insufficient water?
A. Overheating of exposed heating surfaces
B. Excessive condensate return
C. Reduced combustion temperature
D. Excessive feedwater flow
Answer: A
Rationale: Low water can expose tubes or other heating surfaces to direct flame and cause
severe overheating.
8. What is the purpose of a flame safeguard system?
A. Shut off fuel if the required flame is not established or is lost
B. Increase fuel flow after flame failure
C. Maintain boiler water chemistry
D. Control condensate return
Answer: A
Rationale: Preventing continued fuel flow after flame failure helps prevent furnace explosions.
9. Excessive excess air in combustion generally:
A. Increases stack heat loss
B. Eliminates all heat loss
C. Always increases efficiency
D. Prevents combustion
Answer: A
Rationale: Excess air must be heated and can carry additional heat out through the stack.
10. What is the purpose of boiler blowdown?
A. Control dissolved solids and remove sludge
B. Increase boiler-water concentration indefinitely
, C. Increase scale formation
D. Add oxygen
Answer: A
Rationale: Blowdown removes concentrated boiler water and suspended solids.
11. What condition can result from excessive boiler-water dissolved solids?
A. Foaming and steam carryover
B. Improved steam purity
C. Elimination of corrosion
D. Lower conductivity
Answer: A
Rationale: High dissolved-solids concentrations can contribute to foaming and carryover.
12. What is water hammer?
A. A pressure surge caused by sudden changes in fluid flow
B. Normal boiler circulation
C. A water-treatment process
D. A method of reducing steam pressure
Answer: A
Rationale: Rapid movement or stoppage of condensate or water can generate damaging pressure
waves.
13. Which condition is a common cause of water hammer in steam piping?
A. Accumulated condensate
B. Proper drainage
C. Properly functioning steam traps
D. Correct pipe pitch
Answer: A
Rationale: Condensate carried at high velocity can create severe pressure surges.
14. What is the function of a steam trap?
A. Discharge condensate while minimizing live-steam loss
B. Increase boiler pressure
C. Add feedwater
D. Increase dissolved oxygen
Answer: A
Rationale: Steam traps remove condensate and, depending on type, non-condensable gases.
15. What is the approximate conventional heat equivalent of one boiler horsepower?
A. 33,475 Btu/hr
B. 3,475 Btu/hr
rationales 2026/2027 version /instant pdf
1. A boiler safety valve is primarily designed to:
A. Prevent excessive boiler pressure
B. Maintain constant water level
C. Control fuel temperature
D. Remove dissolved solids
Answer: A
Rationale: The safety valve automatically relieves pressure when the boiler reaches its set
pressure.
2. If boiler pressure rises above the normal operating range, the operator should first:
A. Follow the established operating procedure and determine the cause
B. Disable the safety valve
C. Increase firing rate
D. Close all safety devices
Answer: A
Rationale: Abnormal pressure requires immediate assessment and corrective action within
approved procedures.
3. What is the principal purpose of a deaerator?
A. Remove dissolved oxygen and other gases from feedwater
B. Increase dissolved oxygen
C. Remove steam from the boiler
D. Increase boiler pressure
Answer: A
Rationale: Dissolved oxygen can cause serious corrosion, particularly pitting, so deaeration
protects the feedwater system.
4. A boiler with excessive scale will generally have:
A. Reduced heat transfer and increased metal temperature
B. Improved efficiency
C. Lower fuel consumption
D. Better circulation
Answer: A
Rationale: Scale acts as an insulating layer, reducing heat transfer and potentially overheating
boiler metal.
5. What is the primary purpose of an economizer?
A. Recover flue-gas heat to preheat feedwater
B. Cool combustion gases
,C. Remove boiler sludge
D. Reduce feedwater temperature
Answer: A
Rationale: An economizer improves efficiency by recovering waste heat.
6. Superheated steam is steam that:
A. Has been heated above its saturation temperature at a given pressure
B. Contains large amounts of liquid water
C. Is below atmospheric pressure
D. Has been completely condensed
Answer: A
Rationale: Superheating adds sensible heat after the steam has reached saturation.
7. What is the primary danger of firing a boiler with insufficient water?
A. Overheating of exposed heating surfaces
B. Excessive condensate return
C. Reduced combustion temperature
D. Excessive feedwater flow
Answer: A
Rationale: Low water can expose tubes or other heating surfaces to direct flame and cause
severe overheating.
8. What is the purpose of a flame safeguard system?
A. Shut off fuel if the required flame is not established or is lost
B. Increase fuel flow after flame failure
C. Maintain boiler water chemistry
D. Control condensate return
Answer: A
Rationale: Preventing continued fuel flow after flame failure helps prevent furnace explosions.
9. Excessive excess air in combustion generally:
A. Increases stack heat loss
B. Eliminates all heat loss
C. Always increases efficiency
D. Prevents combustion
Answer: A
Rationale: Excess air must be heated and can carry additional heat out through the stack.
10. What is the purpose of boiler blowdown?
A. Control dissolved solids and remove sludge
B. Increase boiler-water concentration indefinitely
, C. Increase scale formation
D. Add oxygen
Answer: A
Rationale: Blowdown removes concentrated boiler water and suspended solids.
11. What condition can result from excessive boiler-water dissolved solids?
A. Foaming and steam carryover
B. Improved steam purity
C. Elimination of corrosion
D. Lower conductivity
Answer: A
Rationale: High dissolved-solids concentrations can contribute to foaming and carryover.
12. What is water hammer?
A. A pressure surge caused by sudden changes in fluid flow
B. Normal boiler circulation
C. A water-treatment process
D. A method of reducing steam pressure
Answer: A
Rationale: Rapid movement or stoppage of condensate or water can generate damaging pressure
waves.
13. Which condition is a common cause of water hammer in steam piping?
A. Accumulated condensate
B. Proper drainage
C. Properly functioning steam traps
D. Correct pipe pitch
Answer: A
Rationale: Condensate carried at high velocity can create severe pressure surges.
14. What is the function of a steam trap?
A. Discharge condensate while minimizing live-steam loss
B. Increase boiler pressure
C. Add feedwater
D. Increase dissolved oxygen
Answer: A
Rationale: Steam traps remove condensate and, depending on type, non-condensable gases.
15. What is the approximate conventional heat equivalent of one boiler horsepower?
A. 33,475 Btu/hr
B. 3,475 Btu/hr
