California Boiler Operator License Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the function of a safety valve on a boiler?
A. Increase pressure
B. Decrease temperature
C. Prevent overpressure
D. Control combustion
A safety valve automatically releases pressure when it exceeds the
set limit, preventing potential boiler explosions.
2. The water level in a boiler should be checked:
A. Once a week
B. Daily
C. Only when there is a leak
D. When pressure is low
Maintaining proper water levels daily is critical to safe boiler
operation.
3. What is the primary purpose of a low water cutoff?
A. Regulate feedwater
B. Shut down the burner if water is low
C. Control steam pressure
, D. Prevent overheating
A low water cutoff shuts off the boiler if the water level drops too
low, avoiding severe damage.
4. In steam boilers, what is the typical maximum pressure for low-
pressure systems?
A. 50 psi
B. 25 psi
C. 15 psi
D. 5 psi
Low-pressure steam boilers are rated for 15 psi or less according to
ASME code.
5. What device removes air and non-condensable gases from a boiler
feedwater system?
A. Deaerator
B. Condensate pump
C. Separator
D. Strainer
A deaerator removes oxygen and other gases to prevent corrosion in
the boiler.
6. What is the purpose of boiler blowdown?
A. Reduce steam pressure
B. Remove sludge and sediments
C. Increase water level
D. Add chemicals
Blowdown removes impurities and sludge to maintain boiler
efficiency and water quality.
7. What does the flame scanner in a boiler do?
A. Measure temperature
B. Detect burner flame
, C. Monitor steam quality
D. Record fuel flow
Flame scanners ensure a flame is present during burner operation to
avoid unsafe conditions.
8. What is the correct action if the water level in the boiler is too high?
A. Add more water
B. Blow down the boiler
C. Increase fuel flow
D. Turn off the feed pump
Blowing down reduces excess water, restoring the proper water
level.
9. What must be done before opening a boiler for internal inspection?
A. Open steam valves
B. Lock out and tag out
C. Increase pressure
D. Drain feedwater
Lockout/tagout procedures are critical to ensure safety during
inspections or maintenance.
10. A boiler horsepower is defined as the ability to:
A. Generate 10 psi steam
B. Evaporate 34.5 lbs of water per hour
C. Hold 10 gallons of water
D. Operate a 10 HP pump
One boiler horsepower equals the ability to evaporate 34.5 lbs of
water into steam per hour at 212°F.
11. Which instrument indicates the steam pressure in the boiler?
A. Flowmeter
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the function of a safety valve on a boiler?
A. Increase pressure
B. Decrease temperature
C. Prevent overpressure
D. Control combustion
A safety valve automatically releases pressure when it exceeds the
set limit, preventing potential boiler explosions.
2. The water level in a boiler should be checked:
A. Once a week
B. Daily
C. Only when there is a leak
D. When pressure is low
Maintaining proper water levels daily is critical to safe boiler
operation.
3. What is the primary purpose of a low water cutoff?
A. Regulate feedwater
B. Shut down the burner if water is low
C. Control steam pressure
, D. Prevent overheating
A low water cutoff shuts off the boiler if the water level drops too
low, avoiding severe damage.
4. In steam boilers, what is the typical maximum pressure for low-
pressure systems?
A. 50 psi
B. 25 psi
C. 15 psi
D. 5 psi
Low-pressure steam boilers are rated for 15 psi or less according to
ASME code.
5. What device removes air and non-condensable gases from a boiler
feedwater system?
A. Deaerator
B. Condensate pump
C. Separator
D. Strainer
A deaerator removes oxygen and other gases to prevent corrosion in
the boiler.
6. What is the purpose of boiler blowdown?
A. Reduce steam pressure
B. Remove sludge and sediments
C. Increase water level
D. Add chemicals
Blowdown removes impurities and sludge to maintain boiler
efficiency and water quality.
7. What does the flame scanner in a boiler do?
A. Measure temperature
B. Detect burner flame
, C. Monitor steam quality
D. Record fuel flow
Flame scanners ensure a flame is present during burner operation to
avoid unsafe conditions.
8. What is the correct action if the water level in the boiler is too high?
A. Add more water
B. Blow down the boiler
C. Increase fuel flow
D. Turn off the feed pump
Blowing down reduces excess water, restoring the proper water
level.
9. What must be done before opening a boiler for internal inspection?
A. Open steam valves
B. Lock out and tag out
C. Increase pressure
D. Drain feedwater
Lockout/tagout procedures are critical to ensure safety during
inspections or maintenance.
10. A boiler horsepower is defined as the ability to:
A. Generate 10 psi steam
B. Evaporate 34.5 lbs of water per hour
C. Hold 10 gallons of water
D. Operate a 10 HP pump
One boiler horsepower equals the ability to evaporate 34.5 lbs of
water into steam per hour at 212°F.
11. Which instrument indicates the steam pressure in the boiler?
A. Flowmeter
