3rd Class Power Engineer B1 Exam Questions
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a boiler steam drum?
A. To increase furnace temperature
B. To separate steam from water
C. To reduce stack losses
D. To store feedwater only
Rationale: The steam drum separates steam from water in water-tube
boilers. Steam rises to the top of the drum where moisture separators
remove water droplets before steam exits to the superheater or steam
system. Proper steam separation ensures dry steam, prevents turbine
damage, and improves efficiency.
2. Which boiler component is designed to recover heat from flue
gases and transfer it to incoming feedwater?
,A. Superheater
B. Air preheater
C. Economizer
D. Steam separator
Rationale: An economizer captures waste heat from exhaust gases
and transfers it to boiler feedwater before it enters the steam drum.
This reduces fuel consumption, improves boiler efficiency, and
minimizes thermal shock.
3. The purpose of a superheater is to:
A. Increase boiler pressure
B. Separate moisture from steam
C. Raise steam temperature above saturation
D. Reduce feedwater temperature
Rationale: A superheater increases the temperature of saturated
steam without increasing its pressure. Superheated steam contains
more energy, reduces condensation in turbines, and improves cycle
efficiency.
4. Boiler blowdown is primarily performed to:
,A. Increase steam pressure
B. Reduce oxygen content only
C. Control dissolved solids in boiler water
D. Increase boiler capacity
Rationale: Blowdown removes concentrated dissolved solids, sludge,
and impurities from the boiler. Controlling Total Dissolved Solids (TDS)
prevents scale formation, foaming, and carryover, improving boiler
reliability and efficiency.
5. What is the function of a deaerator?
A. Increase feedwater pressure
B. Remove dissolved oxygen and carbon dioxide from feedwater
C. Separate steam from water
D. Lower steam temperature
Rationale: Dissolved oxygen and carbon dioxide cause corrosion in
boilers and piping. A deaerator heats feedwater and vents dissolved
gases, significantly reducing corrosion and extending equipment life.
6. Which valve is normally installed directly on a boiler to prevent
excessive pressure?
, A. Globe valve
B. Gate valve
C. Check valve
D. Safety valve
Rationale: A safety valve automatically opens when boiler pressure
exceeds its set point, preventing dangerous overpressure conditions. It
is one of the most critical boiler safety devices.
7. A boiler gauge glass is used to indicate:
A. Steam pressure
B. Steam temperature
C. Water level inside the boiler
D. Feedwater flow rate
Rationale: The gauge glass provides a direct visual indication of the
boiler water level. Maintaining the proper water level is essential to
prevent overheating or flooding of boiler tubes.
8. What is the purpose of boiler water treatment?
A. Increase furnace temperature
B. Reduce draft losses
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a boiler steam drum?
A. To increase furnace temperature
B. To separate steam from water
C. To reduce stack losses
D. To store feedwater only
Rationale: The steam drum separates steam from water in water-tube
boilers. Steam rises to the top of the drum where moisture separators
remove water droplets before steam exits to the superheater or steam
system. Proper steam separation ensures dry steam, prevents turbine
damage, and improves efficiency.
2. Which boiler component is designed to recover heat from flue
gases and transfer it to incoming feedwater?
,A. Superheater
B. Air preheater
C. Economizer
D. Steam separator
Rationale: An economizer captures waste heat from exhaust gases
and transfers it to boiler feedwater before it enters the steam drum.
This reduces fuel consumption, improves boiler efficiency, and
minimizes thermal shock.
3. The purpose of a superheater is to:
A. Increase boiler pressure
B. Separate moisture from steam
C. Raise steam temperature above saturation
D. Reduce feedwater temperature
Rationale: A superheater increases the temperature of saturated
steam without increasing its pressure. Superheated steam contains
more energy, reduces condensation in turbines, and improves cycle
efficiency.
4. Boiler blowdown is primarily performed to:
,A. Increase steam pressure
B. Reduce oxygen content only
C. Control dissolved solids in boiler water
D. Increase boiler capacity
Rationale: Blowdown removes concentrated dissolved solids, sludge,
and impurities from the boiler. Controlling Total Dissolved Solids (TDS)
prevents scale formation, foaming, and carryover, improving boiler
reliability and efficiency.
5. What is the function of a deaerator?
A. Increase feedwater pressure
B. Remove dissolved oxygen and carbon dioxide from feedwater
C. Separate steam from water
D. Lower steam temperature
Rationale: Dissolved oxygen and carbon dioxide cause corrosion in
boilers and piping. A deaerator heats feedwater and vents dissolved
gases, significantly reducing corrosion and extending equipment life.
6. Which valve is normally installed directly on a boiler to prevent
excessive pressure?
, A. Globe valve
B. Gate valve
C. Check valve
D. Safety valve
Rationale: A safety valve automatically opens when boiler pressure
exceeds its set point, preventing dangerous overpressure conditions. It
is one of the most critical boiler safety devices.
7. A boiler gauge glass is used to indicate:
A. Steam pressure
B. Steam temperature
C. Water level inside the boiler
D. Feedwater flow rate
Rationale: The gauge glass provides a direct visual indication of the
boiler water level. Maintaining the proper water level is essential to
prevent overheating or flooding of boiler tubes.
8. What is the purpose of boiler water treatment?
A. Increase furnace temperature
B. Reduce draft losses
