NYC High-Pressure Boiler Operating Engineer License Exam 2026 –
Professional Certification Practice Questions with Answers &
Detailed Rationales, Boiler Operations, Steam Systems, Combustion,
Pressure Controls, Maintenance & NYC Code Compliance
Practice Examination – 190 Multiple-Choice Questions
Question 1
A high-pressure boiler operating engineer observes that the steam pressure gauge and the
water column gauge glass are both functioning normally. However, the low-water cutoff has
tripped repeatedly during the past 24 hours, even though the gauge glass shows a steady
water level. Which of the following is the most likely explanation for this discrepancy?
A. The gauge glass connections are partially blocked, causing a false water level indication.
B. The low-water cutoff float chamber has a restricted equalizing line, causing the float to
sense a lower level than actual.
C. The feedwater pump is oversized for the steaming rate, causing short cycling.
D. The boiler safety valve is leaking, causing a false low-pressure condition.
Correct Answer: B
Explanation:
,A restricted equalizing line in the low-water cutoff float chamber causes the float to respond
sluggishly or incorrectly, creating a false low-water signal while the gauge glass remains
accurate.
Question 2
During a routine inspection of a high-pressure steam boiler, the engineer notices that the
bottom blowdown valve closest to the boiler is a quick-opening valve, while the second valve
is a slow-opening type. The engineer needs to blow down the boiler to reduce dissolved
solids. Which valve should be opened first?
A. The slow-opening valve should be opened first to gradually establish flow.
B. The quick-opening valve should be opened first to establish flow, then the slow-opening
valve controls the blowdown.
C. Both valves should be opened simultaneously to prevent water hammer.
D. The quick-opening valve should be opened last to provide a final quick burst.
Correct Answer: B
Explanation:
Standard practice requires the quick-opening valve nearest the boiler to be opened fully
first, then the slow-opening valve is used to control and regulate the blowdown rate.
Question 3
,A boiler operating engineer observes that the stack temperature has risen from 380°F to
520°F over the course of a week while the boiler is operating at the same firing rate. Steam
output and pressure remain normal. What does this most likely indicate?
A. Improved combustion efficiency due to better fuel atomization.
B. Excessive combustion air causing a higher flame temperature.
C. Fouling of heat transfer surfaces on the fire side or water side.
D. An increase in boiler water alkalinity causing better heat transfer.
Correct Answer: C
Explanation:
A rising stack temperature at constant load indicates reduced heat transfer, most commonly
due to soot buildup on fireside surfaces or scale accumulation on waterside surfaces.
Question 4
The engineer is preparing to start a cold high-pressure boiler after a maintenance shutdown.
The boiler has been hydrostatically tested and the water level is normal. According to best
practices, what should be verified BEFORE establishing a main flame?
A. The main steam stop valve is fully open to allow immediate steam flow.
B. The burner management system has completed its pre-purge cycle and proven
combustion air flow.
, C. The feedwater pump is operating at maximum speed to ensure water is available.
D. The safety valve is manually lifted to verify it operates freely.
Correct Answer: B
Explanation:
Before ignition, the burner management system must complete a pre-purge to remove
combustible gases and prove adequate combustion air flow to prevent furnace explosions.
Question 5
An operating engineer notices that the water level in the gauge glass is fluctuating rapidly
and violently during periods of high steam demand. The feedwater control valve is
modulating continuously. What is the most likely cause of this condition?
A. Boiler water carryover due to high dissolved solids concentration.
B. A partially plugged feedwater check valve causing pulsating flow.
C. Rapid changes in steam demand causing boiler swell and shrink, affecting level indication.
D. A defective pressuretrol causing erratic burner operation.
Correct Answer: C
Explanation:
Professional Certification Practice Questions with Answers &
Detailed Rationales, Boiler Operations, Steam Systems, Combustion,
Pressure Controls, Maintenance & NYC Code Compliance
Practice Examination – 190 Multiple-Choice Questions
Question 1
A high-pressure boiler operating engineer observes that the steam pressure gauge and the
water column gauge glass are both functioning normally. However, the low-water cutoff has
tripped repeatedly during the past 24 hours, even though the gauge glass shows a steady
water level. Which of the following is the most likely explanation for this discrepancy?
A. The gauge glass connections are partially blocked, causing a false water level indication.
B. The low-water cutoff float chamber has a restricted equalizing line, causing the float to
sense a lower level than actual.
C. The feedwater pump is oversized for the steaming rate, causing short cycling.
D. The boiler safety valve is leaking, causing a false low-pressure condition.
Correct Answer: B
Explanation:
,A restricted equalizing line in the low-water cutoff float chamber causes the float to respond
sluggishly or incorrectly, creating a false low-water signal while the gauge glass remains
accurate.
Question 2
During a routine inspection of a high-pressure steam boiler, the engineer notices that the
bottom blowdown valve closest to the boiler is a quick-opening valve, while the second valve
is a slow-opening type. The engineer needs to blow down the boiler to reduce dissolved
solids. Which valve should be opened first?
A. The slow-opening valve should be opened first to gradually establish flow.
B. The quick-opening valve should be opened first to establish flow, then the slow-opening
valve controls the blowdown.
C. Both valves should be opened simultaneously to prevent water hammer.
D. The quick-opening valve should be opened last to provide a final quick burst.
Correct Answer: B
Explanation:
Standard practice requires the quick-opening valve nearest the boiler to be opened fully
first, then the slow-opening valve is used to control and regulate the blowdown rate.
Question 3
,A boiler operating engineer observes that the stack temperature has risen from 380°F to
520°F over the course of a week while the boiler is operating at the same firing rate. Steam
output and pressure remain normal. What does this most likely indicate?
A. Improved combustion efficiency due to better fuel atomization.
B. Excessive combustion air causing a higher flame temperature.
C. Fouling of heat transfer surfaces on the fire side or water side.
D. An increase in boiler water alkalinity causing better heat transfer.
Correct Answer: C
Explanation:
A rising stack temperature at constant load indicates reduced heat transfer, most commonly
due to soot buildup on fireside surfaces or scale accumulation on waterside surfaces.
Question 4
The engineer is preparing to start a cold high-pressure boiler after a maintenance shutdown.
The boiler has been hydrostatically tested and the water level is normal. According to best
practices, what should be verified BEFORE establishing a main flame?
A. The main steam stop valve is fully open to allow immediate steam flow.
B. The burner management system has completed its pre-purge cycle and proven
combustion air flow.
, C. The feedwater pump is operating at maximum speed to ensure water is available.
D. The safety valve is manually lifted to verify it operates freely.
Correct Answer: B
Explanation:
Before ignition, the burner management system must complete a pre-purge to remove
combustible gases and prove adequate combustion air flow to prevent furnace explosions.
Question 5
An operating engineer notices that the water level in the gauge glass is fluctuating rapidly
and violently during periods of high steam demand. The feedwater control valve is
modulating continuously. What is the most likely cause of this condition?
A. Boiler water carryover due to high dissolved solids concentration.
B. A partially plugged feedwater check valve causing pulsating flow.
C. Rapid changes in steam demand causing boiler swell and shrink, affecting level indication.
D. A defective pressuretrol causing erratic burner operation.
Correct Answer: C
Explanation:
