Exam Practice Test 100 Questions And

1st Class Stationary Engineer License Exam Practice Test 100 Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a steam boiler?
• Cool process equipment
• Provide compressed air
• Generate steam for power or heating
• Condense refrigerant

Rationale: Boilers convert water into steam for heat or mechanical work.

2. The Hartford Loop is used to:

• Increase steam pressure
• Prevent water loss from the boiler due to a broken return line
• Increase feedwater temperature 1 / 3

• Reduce blowdown frequency

Rationale: The Hartford Loop prevents boiler dry-firing if a return line fails.

3. The purpose of a boiler safety valve is to:

• Regulate feedwater temperature
• Maintain steam quality
• Prevent boiler overpressure
• Control fuel flow

Rationale: Safety valves protect the boiler by releasing excess pressure.

4. Low-water cutoff devices are required because they:

• Reduce scale buildup
• Prevent boiler operation during dangerously low water conditions
• Maintain steam purity
• Increase combustion efficiency

Rationale: Low water can cause overheating and boiler failure.

• A deaerator removes which gas from feedwater?
• Nitrogen
• Oxygen
• Carbon monoxide
• Argon

Rationale: Oxygen causes corrosion; deaerators remove it via heat and

venting.

• What type of combustion uses excess air? 2 / 3

• Stoichiometric
• Complete combustion
• Incomplete combustion
• Catalytic combustion

Rationale: Complete combustion uses excess air to ensure full fuel burnout.

7. A boiler’s MAWP refers to the:

• Maximum temperature
• Maximum water level
• Maximum allowable working pressure
• Minimum allowable water pressure

Rationale: MAWP is the highest safe pressure the boiler can operate at.

8. Scale on boiler tubes results in:

• Lower stack temperature
• Reduced heat transfer efficiency
• Lower flue gas pressure
• Improved boiler efficiency

Rationale: Scale insulates tubes and reduces heat transfer, increasing fuel

use.

9. Steam traps are used to:

• Increase steam pressure
• Reheat condensate
• Remove condensate without losing steam
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