DC Third Class Stationary Boilers (323)
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary function of a stationary boiler?
A. To generate compressed air
B. To produce steam or hot water
C. To cool industrial equipment
D. To store thermal energy
Answer: B
Rationale: Stationary boilers are designed to generate steam or
hot water for heating, power, or process use.
2. Which fuel is most commonly used in modern stationary boilers?
A. Coal only
B. Wood
C. Natural gas
D. Nuclear fuel
Answer: C
Rationale: Natural gas is widely used due to efficiency, availability,
and cleaner combustion.
3. What device prevents excessive pressure buildup in a boiler?
A. Feedwater pump
B. Pressure gauge
, C. Safety valve
D. Blowdown valve
Answer: C
Rationale: Safety valves automatically release pressure to prevent
explosions.
4. The normal water level in a boiler is monitored using the:
A. Thermometer
B. Sight glass
C. Draft gauge
D. Orsat analyzer
Answer: B
Rationale: The sight glass provides a visual indication of boiler
water level.
5. What condition can cause a boiler to overheat and fail?
A. High water level
B. Low water level
C. Low steam pressure
D. Excessive blowdown
Answer: B
Rationale: Low water exposes heating surfaces, leading to
overheating and damage.
6. Which component adds water to the boiler during operation?
A. Safety valve
B. Feedwater pump
C. Economizer
D. Superheater
Answer: B
, Rationale: The feedwater pump supplies water to maintain proper
boiler level.
7. Blowdown is performed to:
A. Increase steam pressure
B. Remove sludge and impurities
C. Reduce fuel consumption
D. Cool the boiler
Answer: B
Rationale: Blowdown removes dissolved solids that accumulate
during operation.
8. What instrument measures steam pressure?
A. Draft gauge
B. Pressure gauge
C. Flow meter
D. Thermocouple
Answer: B
Rationale: A pressure gauge indicates the internal pressure of the
boiler.
9. Which type of boiler is most common for stationary applications?
A. Fire-tube boiler
B. Once-through boiler
C. Flash boiler
D. Nuclear boiler
Answer: A
Rationale: Fire-tube boilers are widely used due to simplicity and
reliability.
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary function of a stationary boiler?
A. To generate compressed air
B. To produce steam or hot water
C. To cool industrial equipment
D. To store thermal energy
Answer: B
Rationale: Stationary boilers are designed to generate steam or
hot water for heating, power, or process use.
2. Which fuel is most commonly used in modern stationary boilers?
A. Coal only
B. Wood
C. Natural gas
D. Nuclear fuel
Answer: C
Rationale: Natural gas is widely used due to efficiency, availability,
and cleaner combustion.
3. What device prevents excessive pressure buildup in a boiler?
A. Feedwater pump
B. Pressure gauge
, C. Safety valve
D. Blowdown valve
Answer: C
Rationale: Safety valves automatically release pressure to prevent
explosions.
4. The normal water level in a boiler is monitored using the:
A. Thermometer
B. Sight glass
C. Draft gauge
D. Orsat analyzer
Answer: B
Rationale: The sight glass provides a visual indication of boiler
water level.
5. What condition can cause a boiler to overheat and fail?
A. High water level
B. Low water level
C. Low steam pressure
D. Excessive blowdown
Answer: B
Rationale: Low water exposes heating surfaces, leading to
overheating and damage.
6. Which component adds water to the boiler during operation?
A. Safety valve
B. Feedwater pump
C. Economizer
D. Superheater
Answer: B
, Rationale: The feedwater pump supplies water to maintain proper
boiler level.
7. Blowdown is performed to:
A. Increase steam pressure
B. Remove sludge and impurities
C. Reduce fuel consumption
D. Cool the boiler
Answer: B
Rationale: Blowdown removes dissolved solids that accumulate
during operation.
8. What instrument measures steam pressure?
A. Draft gauge
B. Pressure gauge
C. Flow meter
D. Thermocouple
Answer: B
Rationale: A pressure gauge indicates the internal pressure of the
boiler.
9. Which type of boiler is most common for stationary applications?
A. Fire-tube boiler
B. Once-through boiler
C. Flash boiler
D. Nuclear boiler
Answer: A
Rationale: Fire-tube boilers are widely used due to simplicity and
reliability.
