2nd Class Power Engineer B2 Exam Questions
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. The primary purpose of a boiler drum is to:
A. Increase steam pressure
B. Separate steam from water
C. Heat combustion air
D. Remove dissolved gases
Correct Answer: B. Separate steam from water
Rationale: The steam drum is the upper vessel in a water-tube boiler
where steam is separated from the water-steam mixture. Steam rises
to the top of the drum while water returns through downcomers for
recirculation. Effective separation prevents moisture carryover,
protecting turbines and other downstream equipment.
2. A boiler safety valve is primarily designed to:
A. Control steam pressure
B. Increase boiler efficiency
, C. Prevent excessive pressure
D. Regulate feedwater flow
Rationale: Safety valves are the final protective devices against
overpressure. They automatically open when pressure reaches the set
point and close once pressure returns to a safe level. Their proper
operation is essential for personnel and equipment safety.
3. Boiler blowdown is mainly performed to:
A. Increase steam production
B. Cool the boiler
C. Control dissolved and suspended solids
D. Increase combustion efficiency
Rationale: Blowdown removes concentrated impurities from the boiler
water. Without regular blowdown, dissolved solids increase, leading
to scale formation, foaming, and carryover, all of which reduce
efficiency and can damage the boiler.
4. The function of an economizer is to:
A. Heat combustion air
B. Superheat steam
C. Preheat boiler feedwater
D. Cool flue gases
,Rationale: An economizer recovers waste heat from flue gases to
preheat feedwater before it enters the boiler. This improves thermal
efficiency, reduces fuel consumption, and lowers stack temperatures.
5. Which instrument measures boiler water level directly?
A. Pressure gauge
B. Thermometer
C. Gauge glass
D. Flowmeter
Rationale: The gauge glass provides a direct visual indication of the
water level inside the boiler. Operators use it continuously to ensure
the water level remains within safe operating limits.
6. The purpose of a superheater is to:
A. Produce saturated steam
B. Increase boiler pressure
C. Raise steam temperature above saturation
D. Remove moisture from feedwater
Rationale: A superheater adds heat to saturated steam without
increasing pressure. Superheated steam improves turbine efficiency
and reduces the likelihood of condensation during expansion.
7. Scale inside boiler tubes primarily results in:
A. Lower fuel consumption
, B. Better heat transfer
C. Reduced heat transfer and overheating
D. Increased steam quality
Rationale: Scale acts as an insulating layer, reducing heat transfer
from combustion gases to the water. This forces tube metal
temperatures to rise, increasing the risk of tube failure.
8. The function of a deaerator is to:
A. Filter feedwater
B. Add oxygen to feedwater
C. Remove dissolved oxygen and carbon dioxide
D. Increase feedwater pressure
Rationale: Dissolved oxygen and carbon dioxide contribute to
corrosion in boilers and condensate systems. Deaerators remove these
gases through heating and mechanical separation before water enters
the boiler.
9. A feedwater check valve prevents:
A. High steam pressure
B. Scale formation
C. Reverse flow from the boiler
D. Condensate return
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. The primary purpose of a boiler drum is to:
A. Increase steam pressure
B. Separate steam from water
C. Heat combustion air
D. Remove dissolved gases
Correct Answer: B. Separate steam from water
Rationale: The steam drum is the upper vessel in a water-tube boiler
where steam is separated from the water-steam mixture. Steam rises
to the top of the drum while water returns through downcomers for
recirculation. Effective separation prevents moisture carryover,
protecting turbines and other downstream equipment.
2. A boiler safety valve is primarily designed to:
A. Control steam pressure
B. Increase boiler efficiency
, C. Prevent excessive pressure
D. Regulate feedwater flow
Rationale: Safety valves are the final protective devices against
overpressure. They automatically open when pressure reaches the set
point and close once pressure returns to a safe level. Their proper
operation is essential for personnel and equipment safety.
3. Boiler blowdown is mainly performed to:
A. Increase steam production
B. Cool the boiler
C. Control dissolved and suspended solids
D. Increase combustion efficiency
Rationale: Blowdown removes concentrated impurities from the boiler
water. Without regular blowdown, dissolved solids increase, leading
to scale formation, foaming, and carryover, all of which reduce
efficiency and can damage the boiler.
4. The function of an economizer is to:
A. Heat combustion air
B. Superheat steam
C. Preheat boiler feedwater
D. Cool flue gases
,Rationale: An economizer recovers waste heat from flue gases to
preheat feedwater before it enters the boiler. This improves thermal
efficiency, reduces fuel consumption, and lowers stack temperatures.
5. Which instrument measures boiler water level directly?
A. Pressure gauge
B. Thermometer
C. Gauge glass
D. Flowmeter
Rationale: The gauge glass provides a direct visual indication of the
water level inside the boiler. Operators use it continuously to ensure
the water level remains within safe operating limits.
6. The purpose of a superheater is to:
A. Produce saturated steam
B. Increase boiler pressure
C. Raise steam temperature above saturation
D. Remove moisture from feedwater
Rationale: A superheater adds heat to saturated steam without
increasing pressure. Superheated steam improves turbine efficiency
and reduces the likelihood of condensation during expansion.
7. Scale inside boiler tubes primarily results in:
A. Lower fuel consumption
, B. Better heat transfer
C. Reduced heat transfer and overheating
D. Increased steam quality
Rationale: Scale acts as an insulating layer, reducing heat transfer
from combustion gases to the water. This forces tube metal
temperatures to rise, increasing the risk of tube failure.
8. The function of a deaerator is to:
A. Filter feedwater
B. Add oxygen to feedwater
C. Remove dissolved oxygen and carbon dioxide
D. Increase feedwater pressure
Rationale: Dissolved oxygen and carbon dioxide contribute to
corrosion in boilers and condensate systems. Deaerators remove these
gases through heating and mechanical separation before water enters
the boiler.
9. A feedwater check valve prevents:
A. High steam pressure
B. Scale formation
C. Reverse flow from the boiler
D. Condensate return
