,NYC DCAS Plant Maintainer (Hospitals)/Tender
Exam 2026/2027
220 Practice Questions, Answers & Detailed
Solutions
SECTION 1: BOILER OPERATION, MAINTENANCE & SAFETY (Q1–Q50)
Question 1
A high-pressure boiler is operating normally, but the water level in the gauge glass begins to fall rapidly.
What should the plant maintainer check first?
A) Increase the burner firing rate
B) Determine whether there is a feedwater problem or a loss of boiler water
C) Close the main steam stop valve immediately
D) Increase the boiler pressure
Correct Answer: B
Rationale: An abnormal decrease in boiler water level requires immediate investigation of the
feedwater system and possible water loss. Increasing firing rate (A) could make the condition more
dangerous by adding heat to a boiler with insufficient water. Closing the main steam stop valve (C) is not
the first step. Increasing boiler pressure (D) is not a corrective action.
Question 2
What is the primary function of a boiler safety valve?
A) Regulate feedwater temperature
B) Prevent excessive steam pressure
C) Control burner ignition
D) Measure steam flow
Correct Answer: B
Rationale: The safety valve automatically releases steam when pressure reaches its set limit, protecting
the boiler from dangerous overpressure. It does not regulate feedwater temperature (A), control burner
ignition (C), or measure steam flow (D).
Question 3
,Before performing maintenance on a boiler pump, the most important first step is to:
A) Increase the pump speed
B) Isolate the equipment and eliminate hazardous energy sources
C) Add lubricant to the bearings
D) Open the discharge valve
Correct Answer: B
Rationale: Proper isolation and lockout/tagout protect workers from unexpected startup, pressure,
electrical energy, and other hazardous energy. Increasing pump speed (A) would be dangerous. Adding
lubricant (C) and opening the discharge valve (D) are not safety isolation steps.
Question 4
What is the purpose of a boiler burner?
A) Remove sediment from the boiler
B) Mix fuel and air and produce controlled combustion
C) Reduce steam pressure
D) Measure boiler water level
Correct Answer: B
Rationale: The burner provides controlled mixing of fuel and combustion air and produces the heat
required to generate steam. It does not remove sediment (A), reduce steam pressure (C), or measure
water level (D).
Question 5
If a burner fails to establish flame during the normal ignition sequence, what should be done?
A) Immediately attempt to relight the burner
B) Purge the combustion chamber before attempting reignition
C) Increase the fuel supply
D) Open the manual gas valve fully
Correct Answer: B
Rationale: The combustion chamber must be purged of any unburned fuel before attempting reignition
to prevent explosion. Immediately relighting (A) without purging is extremely dangerous. Increasing fuel
supply (C) and opening the manual gas valve (D) without proper purging would also be dangerous.
Question 6
The water column on a boiler serves what primary purpose?
, A) To increase steam pressure
B) To reduce water level fluctuations in the gauge glass so the true water level can be observed
C) To heat the feedwater
D) To store excess steam
Correct Answer: B
Rationale: The water column dampens the turbulence in the boiler water so the gauge glass shows a
more accurate, stable water level. It does not increase pressure (A), heat feedwater (C), or store steam
(D).
Question 7
How often should a boiler's low-water cutoff be tested?
A) Once per year
B) Once per month
C) Daily or as required by code
D) Only when the boiler is installed
Correct Answer: C
Rationale: Low-water cutoffs should be tested daily or per code requirements to ensure they function
properly. Annual (A) and monthly (B) testing may not be sufficient for safety-critical devices. Testing only
at installation (D) is inadequate.
Question 8
What is the purpose of boiler blowdown?
A) To increase steam production
B) To remove dissolved solids and sludge from the boiler water
C) To add chemicals to the boiler water
D) To cool the boiler down
Correct Answer: B
Rationale: Blowdown removes dissolved solids, sludge, and impurities that accumulate in boiler water,
preventing scale and corrosion. It does not increase steam production (A), add chemicals (C), or cool the
boiler (D).
Question 9
A boiler gauge glass shows the water level at the very bottom of the visible range. What is the correct
immediate action?
Exam 2026/2027
220 Practice Questions, Answers & Detailed
Solutions
SECTION 1: BOILER OPERATION, MAINTENANCE & SAFETY (Q1–Q50)
Question 1
A high-pressure boiler is operating normally, but the water level in the gauge glass begins to fall rapidly.
What should the plant maintainer check first?
A) Increase the burner firing rate
B) Determine whether there is a feedwater problem or a loss of boiler water
C) Close the main steam stop valve immediately
D) Increase the boiler pressure
Correct Answer: B
Rationale: An abnormal decrease in boiler water level requires immediate investigation of the
feedwater system and possible water loss. Increasing firing rate (A) could make the condition more
dangerous by adding heat to a boiler with insufficient water. Closing the main steam stop valve (C) is not
the first step. Increasing boiler pressure (D) is not a corrective action.
Question 2
What is the primary function of a boiler safety valve?
A) Regulate feedwater temperature
B) Prevent excessive steam pressure
C) Control burner ignition
D) Measure steam flow
Correct Answer: B
Rationale: The safety valve automatically releases steam when pressure reaches its set limit, protecting
the boiler from dangerous overpressure. It does not regulate feedwater temperature (A), control burner
ignition (C), or measure steam flow (D).
Question 3
,Before performing maintenance on a boiler pump, the most important first step is to:
A) Increase the pump speed
B) Isolate the equipment and eliminate hazardous energy sources
C) Add lubricant to the bearings
D) Open the discharge valve
Correct Answer: B
Rationale: Proper isolation and lockout/tagout protect workers from unexpected startup, pressure,
electrical energy, and other hazardous energy. Increasing pump speed (A) would be dangerous. Adding
lubricant (C) and opening the discharge valve (D) are not safety isolation steps.
Question 4
What is the purpose of a boiler burner?
A) Remove sediment from the boiler
B) Mix fuel and air and produce controlled combustion
C) Reduce steam pressure
D) Measure boiler water level
Correct Answer: B
Rationale: The burner provides controlled mixing of fuel and combustion air and produces the heat
required to generate steam. It does not remove sediment (A), reduce steam pressure (C), or measure
water level (D).
Question 5
If a burner fails to establish flame during the normal ignition sequence, what should be done?
A) Immediately attempt to relight the burner
B) Purge the combustion chamber before attempting reignition
C) Increase the fuel supply
D) Open the manual gas valve fully
Correct Answer: B
Rationale: The combustion chamber must be purged of any unburned fuel before attempting reignition
to prevent explosion. Immediately relighting (A) without purging is extremely dangerous. Increasing fuel
supply (C) and opening the manual gas valve (D) without proper purging would also be dangerous.
Question 6
The water column on a boiler serves what primary purpose?
, A) To increase steam pressure
B) To reduce water level fluctuations in the gauge glass so the true water level can be observed
C) To heat the feedwater
D) To store excess steam
Correct Answer: B
Rationale: The water column dampens the turbulence in the boiler water so the gauge glass shows a
more accurate, stable water level. It does not increase pressure (A), heat feedwater (C), or store steam
(D).
Question 7
How often should a boiler's low-water cutoff be tested?
A) Once per year
B) Once per month
C) Daily or as required by code
D) Only when the boiler is installed
Correct Answer: C
Rationale: Low-water cutoffs should be tested daily or per code requirements to ensure they function
properly. Annual (A) and monthly (B) testing may not be sufficient for safety-critical devices. Testing only
at installation (D) is inadequate.
Question 8
What is the purpose of boiler blowdown?
A) To increase steam production
B) To remove dissolved solids and sludge from the boiler water
C) To add chemicals to the boiler water
D) To cool the boiler down
Correct Answer: B
Rationale: Blowdown removes dissolved solids, sludge, and impurities that accumulate in boiler water,
preventing scale and corrosion. It does not increase steam production (A), add chemicals (C), or cool the
boiler (D).
Question 9
A boiler gauge glass shows the water level at the very bottom of the visible range. What is the correct
immediate action?
