CO Boiler Operator Licensing Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a safety valve on a boiler?
A. Regulate water temperature
B. Control feedwater flow
C. Prevent boiler overpressure
D. Reduce fuel consumption
Rationale: Safety valves protect the boiler by releasing excess pressure to
avoid dangerous overpressure conditions.
2. The steam pressure in a boiler is typically measured in:
A. Kilowatts
B. Cubic feet
C. PSI
D. BTUs
Rationale: Boiler pressure gauges indicate pressure in pounds per square
inch (PSI).
3. A low-water cutoff device is designed to:
A. Increase fuel flow
B. Shut down the burner if water level is too low
C. Add chemicals to the boiler
D. Open the safety valve
Rationale: Low-water cutoffs prevent dry firing, which can destroy the
boiler.
,4. What is the function of boiler blowdown?
A. Raise steam pressure
B. Cool the boiler
C. Increase water hardness
D. Remove sediment and dissolved solids
Rationale: Blowdown clears impurities accumulated at the bottom of the
boiler.
5. Feedwater pumps are used to:
A. Create steam
B. Supply water to the boiler under pressure
C. Vent gases
D. Control combustion air
Rationale: Feedwater pumps maintain proper water levels by supplying
pressurized water.
6. The ASME stamp on a boiler indicates:
A. Fuel type
B. Boiler meets ASME construction standards
C. Warranty duration
D. Local inspection date
Rationale: ASME certification verifies the boiler is built to safety and
performance standards.
7. Steam traps are used to:
A. Increase steam temperature
B. Remove condensate without losing live steam
C. Remove soot
D. Add treatment chemicals
Rationale: Steam traps keep steam systems efficient by draining
condensate.
8. A water column is used with the gauge glass to:
, A. Filter water
B. Provide a stable water level reading
C. Increase pressure
D. Purify steam
Rationale: Water columns dampen fluctuations to give accurate level
readings.
9. The device that prevents backflow from the boiler feed system is:
A. Safety valve
B. Check valve
C. Blowdown valve
D. Low-water cutoff
Rationale: Check valves allow flow in only one direction, preventing
backflow.
10. The primary purpose of boiler water treatment is to:
A. Lower steam temperature
B. Increase fuel efficiency
C. Prevent scale and corrosion
D. Increase feedwater pH
Rationale: Treatment protects internal surfaces from deposits and
corrosion.
11. What is flash steam?
A. Steam used for blowdown
B. Steam formed when hot condensate is released to lower pressure
C. Waste steam
D. Steam formed at start-up
Rationale: Flash steam occurs when high-temperature condensate flashes
into steam at reduced pressure.
12. Boiler efficiency is defined as the ratio of:
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a safety valve on a boiler?
A. Regulate water temperature
B. Control feedwater flow
C. Prevent boiler overpressure
D. Reduce fuel consumption
Rationale: Safety valves protect the boiler by releasing excess pressure to
avoid dangerous overpressure conditions.
2. The steam pressure in a boiler is typically measured in:
A. Kilowatts
B. Cubic feet
C. PSI
D. BTUs
Rationale: Boiler pressure gauges indicate pressure in pounds per square
inch (PSI).
3. A low-water cutoff device is designed to:
A. Increase fuel flow
B. Shut down the burner if water level is too low
C. Add chemicals to the boiler
D. Open the safety valve
Rationale: Low-water cutoffs prevent dry firing, which can destroy the
boiler.
,4. What is the function of boiler blowdown?
A. Raise steam pressure
B. Cool the boiler
C. Increase water hardness
D. Remove sediment and dissolved solids
Rationale: Blowdown clears impurities accumulated at the bottom of the
boiler.
5. Feedwater pumps are used to:
A. Create steam
B. Supply water to the boiler under pressure
C. Vent gases
D. Control combustion air
Rationale: Feedwater pumps maintain proper water levels by supplying
pressurized water.
6. The ASME stamp on a boiler indicates:
A. Fuel type
B. Boiler meets ASME construction standards
C. Warranty duration
D. Local inspection date
Rationale: ASME certification verifies the boiler is built to safety and
performance standards.
7. Steam traps are used to:
A. Increase steam temperature
B. Remove condensate without losing live steam
C. Remove soot
D. Add treatment chemicals
Rationale: Steam traps keep steam systems efficient by draining
condensate.
8. A water column is used with the gauge glass to:
, A. Filter water
B. Provide a stable water level reading
C. Increase pressure
D. Purify steam
Rationale: Water columns dampen fluctuations to give accurate level
readings.
9. The device that prevents backflow from the boiler feed system is:
A. Safety valve
B. Check valve
C. Blowdown valve
D. Low-water cutoff
Rationale: Check valves allow flow in only one direction, preventing
backflow.
10. The primary purpose of boiler water treatment is to:
A. Lower steam temperature
B. Increase fuel efficiency
C. Prevent scale and corrosion
D. Increase feedwater pH
Rationale: Treatment protects internal surfaces from deposits and
corrosion.
11. What is flash steam?
A. Steam used for blowdown
B. Steam formed when hot condensate is released to lower pressure
C. Waste steam
D. Steam formed at start-up
Rationale: Flash steam occurs when high-temperature condensate flashes
into steam at reduced pressure.
12. Boiler efficiency is defined as the ratio of:
