NYC CUSTODIAN ENGINEER EXAM NEWEST 2026/
2027 TEST BANK/ NYC CUSTODIAN ENGINEER EXAM
PREP WITH COMPLETE 300 REAL EXAM QUESTIONS
AND CORRECT VERIFIED ANSWERS/ ALREADY
GRADED A+ (MOST RECENT!!)
A building's domestic-water pressure fluctuates sharply whenever a large
fixture is opened and closed. The incoming pressure is stable, but the
pressure-reducing valve has not been serviced for years. What
component should be investigated?
A. Pressure-reducing valve
B. Boiler burner
C. Condensate pump
D. Cooling-tower fill – Correct Answer - A
A malfunctioning pressure-reducing valve can cause unstable
downstream pressure.
A steam boiler repeatedly reaches a low-water cutoff during high firing,
although the sight glass appears normal at low fire. What phenomenon
should be considered?
A. Flame impingement
B. Boiler-water surging
C. Excessive stack draft
D. Condenser flooding – Correct Answer - B
Surging can cause the visible boiler-water level to fluctuate significantly.
pg. 1
,A boiler flame becomes unstable at high fire. Gas pressure is steady,
burner linkage moves freely, and combustion readings show inadequate
oxygen. What should be investigated?
A. Condensate temperature
B. Combustion-air and burner adjustment
C. Blowdown frequency
D. Feedwater hardness - Correct Answer - B
Insufficient combustion air can destabilize the flame and impair
combustion.
A building has adequate first-floor heating but overheating on upper
floors. Pump differential pressure is higher than normal. What condition
best fits these findings?
A. Excessive system flow
B. Insufficient boiler capacity
C. Reduced boiler conductivity
D. Excessive combustion-air temperature - Correct Answer - A
Excessive differential pressure can cause excessive flow through heating
zones.
A steam-line pressure gauge remains unchanged while other gauges
respond normally. The external sensing line appears intact. What should
be checked?
A. Burner flame color
B. Gauge isolation and sensing passage
C. Motor insulation
D. Expansion-tank pressure - Correct Answer - B
pg. 2
,A blocked or isolated sensing connection can prevent accurate pressure
indication.
A hot-water heating system repeatedly loses pressure after operation. No
visible leak exists, and pressure drops below normal when the system
cools. Which component deserves close inspection?
A. Steam trap
B. Air filter
C. Expansion tank
D. Combustion blower - Correct Answer - C
A defective or improperly charged expansion tank can cause abnormal
pressure changes.
A boiler burner flame strikes the refractory instead of remaining
properly shaped. The nozzle is clean. What can result if the condition
continues?
A. Improved efficiency
B. Increased water circulation
C. Lower condensate temperature
D. Refractory damage and incomplete combustion - Correct Answer - D.
Flame impingement can damage refractory and indicate poor burner
adjustment.
A replacement three-phase motor has the correct horsepower and voltage
but rotates the driven equipment in the wrong direction. What should be
verified?
A. Refrigerant charge
pg. 3
, B. Phase sequence
C. Boiler-water pH
D. Seal material - Correct Answer -B
Incorrect phase sequence can reverse three-phase motor rotation.
A domestic hot-water system maintains proper storage temperature, but
distant fixtures receive hot water slowly. The return line is cool even
though the recirculation pump runs. What should be investigated?
A. Loss of effective return circulation
B. Boiler stack temperature
C. Main steam pressure
D. Electrical service size – Correct Answer - A
A cool return line suggests inadequate circulation through the return
system.
A boiler flame signal becomes erratic whenever a large electrical load
starts nearby. Burner controls otherwise appear normal. What should be
checked?
A. Radiator vents
B. Expansion-tank volume
C. Condensate temperature
D. Electrical supply and grounding - Correct Answer - D
Electrical disturbances can interfere with flame-detection circuits.
pg. 4
2027 TEST BANK/ NYC CUSTODIAN ENGINEER EXAM
PREP WITH COMPLETE 300 REAL EXAM QUESTIONS
AND CORRECT VERIFIED ANSWERS/ ALREADY
GRADED A+ (MOST RECENT!!)
A building's domestic-water pressure fluctuates sharply whenever a large
fixture is opened and closed. The incoming pressure is stable, but the
pressure-reducing valve has not been serviced for years. What
component should be investigated?
A. Pressure-reducing valve
B. Boiler burner
C. Condensate pump
D. Cooling-tower fill – Correct Answer - A
A malfunctioning pressure-reducing valve can cause unstable
downstream pressure.
A steam boiler repeatedly reaches a low-water cutoff during high firing,
although the sight glass appears normal at low fire. What phenomenon
should be considered?
A. Flame impingement
B. Boiler-water surging
C. Excessive stack draft
D. Condenser flooding – Correct Answer - B
Surging can cause the visible boiler-water level to fluctuate significantly.
pg. 1
,A boiler flame becomes unstable at high fire. Gas pressure is steady,
burner linkage moves freely, and combustion readings show inadequate
oxygen. What should be investigated?
A. Condensate temperature
B. Combustion-air and burner adjustment
C. Blowdown frequency
D. Feedwater hardness - Correct Answer - B
Insufficient combustion air can destabilize the flame and impair
combustion.
A building has adequate first-floor heating but overheating on upper
floors. Pump differential pressure is higher than normal. What condition
best fits these findings?
A. Excessive system flow
B. Insufficient boiler capacity
C. Reduced boiler conductivity
D. Excessive combustion-air temperature - Correct Answer - A
Excessive differential pressure can cause excessive flow through heating
zones.
A steam-line pressure gauge remains unchanged while other gauges
respond normally. The external sensing line appears intact. What should
be checked?
A. Burner flame color
B. Gauge isolation and sensing passage
C. Motor insulation
D. Expansion-tank pressure - Correct Answer - B
pg. 2
,A blocked or isolated sensing connection can prevent accurate pressure
indication.
A hot-water heating system repeatedly loses pressure after operation. No
visible leak exists, and pressure drops below normal when the system
cools. Which component deserves close inspection?
A. Steam trap
B. Air filter
C. Expansion tank
D. Combustion blower - Correct Answer - C
A defective or improperly charged expansion tank can cause abnormal
pressure changes.
A boiler burner flame strikes the refractory instead of remaining
properly shaped. The nozzle is clean. What can result if the condition
continues?
A. Improved efficiency
B. Increased water circulation
C. Lower condensate temperature
D. Refractory damage and incomplete combustion - Correct Answer - D.
Flame impingement can damage refractory and indicate poor burner
adjustment.
A replacement three-phase motor has the correct horsepower and voltage
but rotates the driven equipment in the wrong direction. What should be
verified?
A. Refrigerant charge
pg. 3
, B. Phase sequence
C. Boiler-water pH
D. Seal material - Correct Answer -B
Incorrect phase sequence can reverse three-phase motor rotation.
A domestic hot-water system maintains proper storage temperature, but
distant fixtures receive hot water slowly. The return line is cool even
though the recirculation pump runs. What should be investigated?
A. Loss of effective return circulation
B. Boiler stack temperature
C. Main steam pressure
D. Electrical service size – Correct Answer - A
A cool return line suggests inadequate circulation through the return
system.
A boiler flame signal becomes erratic whenever a large electrical load
starts nearby. Burner controls otherwise appear normal. What should be
checked?
A. Radiator vents
B. Expansion-tank volume
C. Condensate temperature
D. Electrical supply and grounding - Correct Answer - D
Electrical disturbances can interfere with flame-detection circuits.
pg. 4
