2nd Class Power Engineer B3 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 and provide water storage
• C. Remove dissolved gases
• D. Superheat steam
Rationale: The steam drum serves as the point where steam is
separated from the water-steam mixture. It also provides a reserve of
boiler water, allowing for stable water level control and improved
steam quality before steam enters the superheater or distribution
system.
2. What is the main function of a superheater?
• A. Increase boiler water level
• B. Raise steam temperature above its saturation temperature
, • C. Remove moisture from feedwater
• D. Reduce steam pressure
Rationale: A superheater adds sensible heat to saturated steam,
increasing its temperature without increasing its pressure.
Superheated steam improves turbine efficiency and reduces
condensation in steam lines.
3. Boiler blowdown is primarily performed to:
• A. Increase steam production
• B. Reduce fuel consumption
• C. Control dissolved and suspended solids
• D. Raise boiler pressure
Rationale: Blowdown removes concentrated dissolved minerals and
suspended solids from the boiler water. This prevents scaling,
foaming, carryover, and corrosion while maintaining acceptable water
chemistry.
4. A safety valve on a boiler is designed to:
• A. Control boiler water level
• B. Prevent overpressure by releasing steam
• C. Remove condensate
, • D. Measure steam flow
Rationale: Safety valves automatically open when pressure exceeds a
preset limit, preventing dangerous overpressure conditions that could
lead to equipment damage or catastrophic failure.
5. Which boiler component improves heat transfer by recovering
heat from flue gases?
• A. Steam drum
• B. Economizer
• C. Air separator
• D. Mud drum
Rationale: An economizer captures waste heat from flue gases to
preheat boiler feedwater. This reduces fuel consumption and increases
overall boiler efficiency.
6. The purpose of a deaerator is to:
• A. Increase feedwater pressure
• B. Remove dissolved oxygen and carbon dioxide
• C. Separate steam from water
• D. Increase condensate temperature
, Rationale: Dissolved oxygen and carbon dioxide contribute
significantly to corrosion in boilers and piping. A deaerator removes
these gases through heating and mechanical venting.
7. Which instrument is commonly used to indicate boiler water
level?
• A. Pressure gauge
• B. Thermocouple
• C. Gauge glass
• D. Flow meter
Rationale: The gauge glass provides operators with a direct visual
indication of the boiler water level, allowing safe monitoring during
operation.
8. Low boiler water level is dangerous because it can:
• A. Reduce condensate return
• B. Lower fuel efficiency only
• C. Expose heating surfaces, causing overheating
• D. Increase steam quality
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 and provide water storage
• C. Remove dissolved gases
• D. Superheat steam
Rationale: The steam drum serves as the point where steam is
separated from the water-steam mixture. It also provides a reserve of
boiler water, allowing for stable water level control and improved
steam quality before steam enters the superheater or distribution
system.
2. What is the main function of a superheater?
• A. Increase boiler water level
• B. Raise steam temperature above its saturation temperature
, • C. Remove moisture from feedwater
• D. Reduce steam pressure
Rationale: A superheater adds sensible heat to saturated steam,
increasing its temperature without increasing its pressure.
Superheated steam improves turbine efficiency and reduces
condensation in steam lines.
3. Boiler blowdown is primarily performed to:
• A. Increase steam production
• B. Reduce fuel consumption
• C. Control dissolved and suspended solids
• D. Raise boiler pressure
Rationale: Blowdown removes concentrated dissolved minerals and
suspended solids from the boiler water. This prevents scaling,
foaming, carryover, and corrosion while maintaining acceptable water
chemistry.
4. A safety valve on a boiler is designed to:
• A. Control boiler water level
• B. Prevent overpressure by releasing steam
• C. Remove condensate
, • D. Measure steam flow
Rationale: Safety valves automatically open when pressure exceeds a
preset limit, preventing dangerous overpressure conditions that could
lead to equipment damage or catastrophic failure.
5. Which boiler component improves heat transfer by recovering
heat from flue gases?
• A. Steam drum
• B. Economizer
• C. Air separator
• D. Mud drum
Rationale: An economizer captures waste heat from flue gases to
preheat boiler feedwater. This reduces fuel consumption and increases
overall boiler efficiency.
6. The purpose of a deaerator is to:
• A. Increase feedwater pressure
• B. Remove dissolved oxygen and carbon dioxide
• C. Separate steam from water
• D. Increase condensate temperature
, Rationale: Dissolved oxygen and carbon dioxide contribute
significantly to corrosion in boilers and piping. A deaerator removes
these gases through heating and mechanical venting.
7. Which instrument is commonly used to indicate boiler water
level?
• A. Pressure gauge
• B. Thermocouple
• C. Gauge glass
• D. Flow meter
Rationale: The gauge glass provides operators with a direct visual
indication of the boiler water level, allowing safe monitoring during
operation.
8. Low boiler water level is dangerous because it can:
• A. Reduce condensate return
• B. Lower fuel efficiency only
• C. Expose heating surfaces, causing overheating
• D. Increase steam quality
