NYC Custodian Engineer Exam Practice Test | 200
Questions with Verified Answers & Rationales | DCAS Civil
Service Exam Prep 2026-2027 | NYC DOE Custodian
Engineer Certification .pdf
COVERAGE BY SECTION
Section Topic Questions
1 Boiler Operations & Steam Systems 1–40
2 HVAC Systems & Refrigeration 41–70
3 Electrical Systems & Motor Controls 71–90
4 Plumbing Systems & Backflow Prevention 91–110
5 Fire Safety & FDNY Codes 111–135
6 Building Maintenance & Preventive Programs 136–155
7 Safety Regulations & Environmental Compliance 156–175
8 Administrative Management & NYC Codes 176–200
,Total Questions: 200 | Passing Score: 70% | Exam Authority: NYC Department of Citywide
Administrative Services (DCAS) | Primary Employer: NYC Department of Education (DOE) | Key
Regulations: NYC Mechanical Code, NYC Fire Code, ASME Boiler Code, Local Law
97 | Certifications Referenced: FDNY P-99 (Low-Pressure Boiler), S-95 (Fire Alarm), F-03 (Portable
Extinguisher) | Question Format: Multiple-choice, scenario-based
Section 1: Boiler Operations & Steam Systems (Questions 1–40)
1. A Custodian Engineer notices a faint odor of natural gas in a school boiler room. What is the
FIRST course of action?
a) Locate the main gas shut-off valve and close it
b) Open all windows and doors to ventilate the area
c) Evacuate the area and call 911 from a remote location
d) Attempt to locate the leak using a soapy water solution
Any action that could create a spark, including using a phone in the area or operating electrical switches,
poses an ignition risk. Evacuation and calling from a safe remote location is the mandated first step per
FDNY safety protocols.
,2. According to NYC Mechanical Code, what is the maximum allowable pressure for a low-pressure
steam boiler?
a) 5 psi
b) 15 psi
c) 100 psi
d) 150 psi
Low-pressure steam boilers are limited to 15 psig; any boiler operating above this pressure requires a
different class of licensure and stricter operating protocols.
3. A three-phase induction motor hums but fails to start. What is the most probable cause?
a) Open circuit in the run winding
b) Seized bearing
c) Single-phasing condition (loss of one phase)
d) Low voltage to all three phases
A three-phase motor that hums and won't start is a classic symptom of single-phasing, where one power
line is disconnected and the motor lacks the rotating magnetic field needed for starting torque.
4. A school reports a "rotten egg" smell from a classroom sink. What is the most likely source?
, a) Natural gas leak from a nearby appliance
b) Sewer gas from a dried-out floor drain trap
c) Leaking battery acid
d) Decomposing organic matter in the wall
The "rotten egg" smell is hydrogen sulfide, a common component of sewer gas. A dried-out floor drain trap
allows sewer gas to enter the building.
5. What is the primary purpose of a Low-Water Cutoff (LWCO) on a steam boiler?
a) To increase water pressure
b) To regulate steam temperature
c) To shut off the fuel supply if water level drops below a safe point
d) To measure water quality
The low-water cutoff is the most critical safety device on a boiler, preventing a dry-fire condition which could
lead to a catastrophic boiler explosion.
6. According to NYC Fire Code, how often must fire drills be conducted in K-12 schools?
a) Semi-annually
b) Quarterly
Questions with Verified Answers & Rationales | DCAS Civil
Service Exam Prep 2026-2027 | NYC DOE Custodian
Engineer Certification .pdf
COVERAGE BY SECTION
Section Topic Questions
1 Boiler Operations & Steam Systems 1–40
2 HVAC Systems & Refrigeration 41–70
3 Electrical Systems & Motor Controls 71–90
4 Plumbing Systems & Backflow Prevention 91–110
5 Fire Safety & FDNY Codes 111–135
6 Building Maintenance & Preventive Programs 136–155
7 Safety Regulations & Environmental Compliance 156–175
8 Administrative Management & NYC Codes 176–200
,Total Questions: 200 | Passing Score: 70% | Exam Authority: NYC Department of Citywide
Administrative Services (DCAS) | Primary Employer: NYC Department of Education (DOE) | Key
Regulations: NYC Mechanical Code, NYC Fire Code, ASME Boiler Code, Local Law
97 | Certifications Referenced: FDNY P-99 (Low-Pressure Boiler), S-95 (Fire Alarm), F-03 (Portable
Extinguisher) | Question Format: Multiple-choice, scenario-based
Section 1: Boiler Operations & Steam Systems (Questions 1–40)
1. A Custodian Engineer notices a faint odor of natural gas in a school boiler room. What is the
FIRST course of action?
a) Locate the main gas shut-off valve and close it
b) Open all windows and doors to ventilate the area
c) Evacuate the area and call 911 from a remote location
d) Attempt to locate the leak using a soapy water solution
Any action that could create a spark, including using a phone in the area or operating electrical switches,
poses an ignition risk. Evacuation and calling from a safe remote location is the mandated first step per
FDNY safety protocols.
,2. According to NYC Mechanical Code, what is the maximum allowable pressure for a low-pressure
steam boiler?
a) 5 psi
b) 15 psi
c) 100 psi
d) 150 psi
Low-pressure steam boilers are limited to 15 psig; any boiler operating above this pressure requires a
different class of licensure and stricter operating protocols.
3. A three-phase induction motor hums but fails to start. What is the most probable cause?
a) Open circuit in the run winding
b) Seized bearing
c) Single-phasing condition (loss of one phase)
d) Low voltage to all three phases
A three-phase motor that hums and won't start is a classic symptom of single-phasing, where one power
line is disconnected and the motor lacks the rotating magnetic field needed for starting torque.
4. A school reports a "rotten egg" smell from a classroom sink. What is the most likely source?
, a) Natural gas leak from a nearby appliance
b) Sewer gas from a dried-out floor drain trap
c) Leaking battery acid
d) Decomposing organic matter in the wall
The "rotten egg" smell is hydrogen sulfide, a common component of sewer gas. A dried-out floor drain trap
allows sewer gas to enter the building.
5. What is the primary purpose of a Low-Water Cutoff (LWCO) on a steam boiler?
a) To increase water pressure
b) To regulate steam temperature
c) To shut off the fuel supply if water level drops below a safe point
d) To measure water quality
The low-water cutoff is the most critical safety device on a boiler, preventing a dry-fire condition which could
lead to a catastrophic boiler explosion.
6. According to NYC Fire Code, how often must fire drills be conducted in K-12 schools?
a) Semi-annually
b) Quarterly
