Contractor Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. The main function of a boiler safety valve is to
A. Regulate steam pressure
B. Prevent overpressure by releasing excess steam
C. Maintain water level
D. Control fuel flow
It ensures the boiler does not exceed design pressure limits.
2. The ASME Boiler and Pressure Vessel Code Section I applies
primarily to
A. Heating boilers
B. Power boilers
C. Pressure vessels
D. Piping systems
Section I covers construction of power boilers.
3. The term “hydrostatic test” refers to
A. Testing a vessel with water pressure
B. Testing with air
C. Measuring fuel pressure
D. Leak testing with gas
Hydrostatic tests use water to check integrity under pressure.
,4. The “blowdown” in a boiler is used to
A. Reduce fuel use
B. Remove sediment and dissolved solids
C. Increase water pressure
D. Vent steam
It helps prevent scale formation and corrosion.
5. The minimum clearance in front of a boiler for servicing is
generally
A. 12 inches
B. 18 inches
C. 36 inches
D. 48 inches
Most codes require at least 3 feet clearance for maintenance.
6. A low-water cutoff device is designed to
A. Control feedwater
B. Maintain steam pressure
C. Shut down boiler when water level is too low
D. Monitor fuel rate
Prevents damage caused by operating without sufficient water.
7. A pressure gauge should be calibrated at least
A. Every month
B. Annually
C. Every five years
D. Only if replaced
Annual calibration ensures accuracy and safety.
8. In a fire-tube boiler, the gases of combustion
A. Surround the tubes
, B. Pass through the tubes
C. Flow above the tubes
D. Enter the water drum
Fire-tube boilers have hot gases flowing inside tubes surrounded
by water.
9. The term “MAWP” means
A. Minimum allowable working pressure
B. Maximum allowable working pressure
C. Mechanical automatic water pressure
D. Manual air water purge
MAWP is the maximum safe pressure a boiler can operate at.
10. Fusible plugs are primarily used to
A. Prevent overheating due to low water
B. Measure temperature
C. Drain condensate
D. Maintain pressure balance
They melt when overheated, releasing pressure to avoid
explosion.
11. The blow-off valve should be located at the
A. Top of the boiler
B. Lowest point of the boiler
C. Near the safety valve
D. Middle section
It allows removal of sludge and sediment from the bottom.
12. A boiler’s “drum” refers to
A. A large cylindrical vessel containing steam and water
B. A pressure gauge