Power Engineer Third Class Examination
Questions With Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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1. What is the primary purpose of a boiler safety valve?
A. To regulate feedwater flow
B. To control steam temperature
C. To relieve excess pressure from the boiler
D. To remove sediment from the boiler
Rationale: A safety valve is a critical boiler safety device designed to
automatically open when pressure exceeds a preset limit. This
prevents dangerous overpressure conditions that could result in boiler
explosion, equipment damage, or injury.
2. Which instrument is commonly used to measure boiler steam
pressure?
A. Thermometer
B. Hydrometer
,C. Pressure gauge
D. Flow meter
Rationale: A pressure gauge measures the internal pressure of steam
or other fluids within a system. Operators rely on pressure gauges to
ensure boilers operate within safe design limits.
3. What is the purpose of boiler blowdown?
A. To increase steam pressure
B. To remove sludge and dissolved solids from the boiler
C. To cool the boiler rapidly
D. To increase water level
Rationale: Blowdown removes impurities, sludge, and dissolved solids
that accumulate in the boiler water. This process helps maintain water
quality, improves efficiency, and prevents scale formation and
corrosion.
4. Which type of pump is most commonly used as a boiler feedwater
pump?
A. Gear pump
B. Diaphragm pump
C. Centrifugal pump
D. Rotary vane pump
,Rationale: Centrifugal pumps are widely used because they can move
large volumes of water efficiently and continuously. They are reliable
and well suited for boiler feedwater service.
5. Low water conditions in a boiler can result in:
A. Increased efficiency
B. Reduced fuel consumption
C. Overheating and possible boiler failure
D. Lower steam temperature only
Rationale: Low water exposes boiler heating surfaces, causing
overheating that may weaken metal and lead to catastrophic failure
or explosion. Maintaining proper water level is one of the most
important boiler safety practices.
6. What is the function of a deaerator?
A. To increase steam temperature
B. To remove dissolved oxygen and gases from feedwater
C. To reduce boiler pressure
D. To separate oil from water
Rationale: Deaerators remove dissolved oxygen and non-condensable
gases that can cause corrosion in boilers and piping systems. Proper
deaeration extends equipment life.
, 7. Which combustion condition produces the highest efficiency?
A. Excessive excess air
B. No excess air
C. Proper air-to-fuel ratio
D. Incomplete combustion
Rationale: Efficient combustion requires the correct balance of fuel
and air. Too much air wastes heat, while too little air causes
incomplete combustion and soot formation.
8. A boiler water column is used to:
A. Measure steam flow
B. Indicate boiler water level
C. Measure fuel usage
D. Reduce boiler pressure
Rationale: The water column provides a visible indication of water
level inside the boiler. Operators use it to ensure safe operating levels
are maintained.
9. Which valve is installed closest to the boiler on a steam outlet
line?
A. Check valve
B. Globe valve
Questions With Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of a boiler safety valve?
A. To regulate feedwater flow
B. To control steam temperature
C. To relieve excess pressure from the boiler
D. To remove sediment from the boiler
Rationale: A safety valve is a critical boiler safety device designed to
automatically open when pressure exceeds a preset limit. This
prevents dangerous overpressure conditions that could result in boiler
explosion, equipment damage, or injury.
2. Which instrument is commonly used to measure boiler steam
pressure?
A. Thermometer
B. Hydrometer
,C. Pressure gauge
D. Flow meter
Rationale: A pressure gauge measures the internal pressure of steam
or other fluids within a system. Operators rely on pressure gauges to
ensure boilers operate within safe design limits.
3. What is the purpose of boiler blowdown?
A. To increase steam pressure
B. To remove sludge and dissolved solids from the boiler
C. To cool the boiler rapidly
D. To increase water level
Rationale: Blowdown removes impurities, sludge, and dissolved solids
that accumulate in the boiler water. This process helps maintain water
quality, improves efficiency, and prevents scale formation and
corrosion.
4. Which type of pump is most commonly used as a boiler feedwater
pump?
A. Gear pump
B. Diaphragm pump
C. Centrifugal pump
D. Rotary vane pump
,Rationale: Centrifugal pumps are widely used because they can move
large volumes of water efficiently and continuously. They are reliable
and well suited for boiler feedwater service.
5. Low water conditions in a boiler can result in:
A. Increased efficiency
B. Reduced fuel consumption
C. Overheating and possible boiler failure
D. Lower steam temperature only
Rationale: Low water exposes boiler heating surfaces, causing
overheating that may weaken metal and lead to catastrophic failure
or explosion. Maintaining proper water level is one of the most
important boiler safety practices.
6. What is the function of a deaerator?
A. To increase steam temperature
B. To remove dissolved oxygen and gases from feedwater
C. To reduce boiler pressure
D. To separate oil from water
Rationale: Deaerators remove dissolved oxygen and non-condensable
gases that can cause corrosion in boilers and piping systems. Proper
deaeration extends equipment life.
, 7. Which combustion condition produces the highest efficiency?
A. Excessive excess air
B. No excess air
C. Proper air-to-fuel ratio
D. Incomplete combustion
Rationale: Efficient combustion requires the correct balance of fuel
and air. Too much air wastes heat, while too little air causes
incomplete combustion and soot formation.
8. A boiler water column is used to:
A. Measure steam flow
B. Indicate boiler water level
C. Measure fuel usage
D. Reduce boiler pressure
Rationale: The water column provides a visible indication of water
level inside the boiler. Operators use it to ensure safe operating levels
are maintained.
9. Which valve is installed closest to the boiler on a steam outlet
line?
A. Check valve
B. Globe valve
