2nd Class Power Engineer A2 Exam Questions
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
Question 1
Which boiler component primarily separates steam from water before
steam enters the superheater?
A. Economizer
B. Steam drum
C. Air preheater
D. Mud drum
Correct Answer: B. Steam drum
Rationale: The steam drum is the primary steam-water separation
vessel in a water-tube boiler. It contains moisture separators and
dryers that remove water droplets from saturated steam before it
flows to the superheater. Proper separation protects downstream
equipment from water carryover, which can damage turbines and
reduce system efficiency.
,Question 2
What is the primary purpose of a superheater?
A. Increase feedwater temperature
B. Remove dissolved oxygen from water
C. Increase steam temperature above saturation
D. Condense exhaust steam
Correct Answer: C. Increase steam temperature above saturation
Rationale: A superheater raises the temperature of saturated steam
above its saturation point without increasing pressure. Superheated
steam contains more energy, improves turbine efficiency, reduces
condensation in steam lines, and minimizes erosion of turbine blades
caused by moisture.
Question 3
What condition is most likely to cause furnace implosion in a boiler?
A. Excessive steam pressure
B. Sudden loss of furnace draft causing negative pressure imbalance
C. High feedwater temperature
D. Low deaerator pressure only
,Correct Answer: B. Sudden loss of furnace draft causing negative
pressure imbalance
Rationale: Furnace implosion occurs when furnace pressure rapidly
becomes excessively negative, often due to failure of draft fans or
improper damper operation. This pressure differential can collapse
furnace walls and seriously damage the boiler.
Question 4
The economizer improves boiler efficiency by:
A. Cooling flue gases below ambient temperature
B. Heating feedwater using waste heat from flue gases
C. Increasing furnace pressure
D. Reducing steam pressure
Correct Answer: B. Heating feedwater using waste heat from flue
gases
Rationale: An economizer recovers heat from exhaust gases that
would otherwise be wasted. This recovered heat preheats feedwater
before it enters the boiler drum, reducing fuel consumption and
improving overall thermal efficiency.
, Question 5
Which instrument measures differential pressure across an orifice
plate?
A. Thermocouple
B. Differential pressure transmitter
C. Rotameter
D. Bourdon tube gauge
Correct Answer: B. Differential pressure transmitter
Rationale: Differential pressure transmitters determine flow by
measuring the pressure difference across an orifice plate. The pressure
drop is proportional to the square of the flow rate, allowing accurate
flow measurement after proper calibration.
Question 6
What is the main purpose of continuous boiler blowdown?
A. Increase boiler pressure
B. Remove suspended solids from the steam drum continuously
C. Add oxygen to feedwater
D. Reduce feedwater temperature
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
Question 1
Which boiler component primarily separates steam from water before
steam enters the superheater?
A. Economizer
B. Steam drum
C. Air preheater
D. Mud drum
Correct Answer: B. Steam drum
Rationale: The steam drum is the primary steam-water separation
vessel in a water-tube boiler. It contains moisture separators and
dryers that remove water droplets from saturated steam before it
flows to the superheater. Proper separation protects downstream
equipment from water carryover, which can damage turbines and
reduce system efficiency.
,Question 2
What is the primary purpose of a superheater?
A. Increase feedwater temperature
B. Remove dissolved oxygen from water
C. Increase steam temperature above saturation
D. Condense exhaust steam
Correct Answer: C. Increase steam temperature above saturation
Rationale: A superheater raises the temperature of saturated steam
above its saturation point without increasing pressure. Superheated
steam contains more energy, improves turbine efficiency, reduces
condensation in steam lines, and minimizes erosion of turbine blades
caused by moisture.
Question 3
What condition is most likely to cause furnace implosion in a boiler?
A. Excessive steam pressure
B. Sudden loss of furnace draft causing negative pressure imbalance
C. High feedwater temperature
D. Low deaerator pressure only
,Correct Answer: B. Sudden loss of furnace draft causing negative
pressure imbalance
Rationale: Furnace implosion occurs when furnace pressure rapidly
becomes excessively negative, often due to failure of draft fans or
improper damper operation. This pressure differential can collapse
furnace walls and seriously damage the boiler.
Question 4
The economizer improves boiler efficiency by:
A. Cooling flue gases below ambient temperature
B. Heating feedwater using waste heat from flue gases
C. Increasing furnace pressure
D. Reducing steam pressure
Correct Answer: B. Heating feedwater using waste heat from flue
gases
Rationale: An economizer recovers heat from exhaust gases that
would otherwise be wasted. This recovered heat preheats feedwater
before it enters the boiler drum, reducing fuel consumption and
improving overall thermal efficiency.
, Question 5
Which instrument measures differential pressure across an orifice
plate?
A. Thermocouple
B. Differential pressure transmitter
C. Rotameter
D. Bourdon tube gauge
Correct Answer: B. Differential pressure transmitter
Rationale: Differential pressure transmitters determine flow by
measuring the pressure difference across an orifice plate. The pressure
drop is proportional to the square of the flow rate, allowing accurate
flow measurement after proper calibration.
Question 6
What is the main purpose of continuous boiler blowdown?
A. Increase boiler pressure
B. Remove suspended solids from the steam drum continuously
C. Add oxygen to feedwater
D. Reduce feedwater temperature
