NYC CUSTODIAN ENGINEER
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS
1. In a low-pressure steam boiler, what is the primary cause of ‘foaming’ which leads to
inaccurate water level readings?
A. High concentration of dissolved solids and oils
B. Low concentration of dissolved solids
C. Excessive boiler blowdown
D. Insufficient fuel oil atomization
Answer: A
Conceptual Explanation: Foaming is caused by a high concentration of dissolved solids,
organics, or oils on the surface of the boiler water, which prevents steam bubbles from
breaking freely.
2. Which type of steam trap uses a corrugated bellows filled with a volatile liquid to open and
close based on temperature?
A. Inverted bucket trap
B. Float and thermostatic trap
,C. Thermostatic trap
D. Thermodynamic disc trap
Answer: C
Conceptual Explanation: Thermostatic traps operate on the principle of temperature
difference using a bellows or bimetallic element.
3. According to NYC FDNY regulations, what color must the caps of a standpipe system’s
Siamese connection be?
A. Yellow
B. Green
C. Red
D. Silver
Answer: C
Conceptual Explanation: Red caps indicate a standpipe system; green indicates a
sprinkler system; yellow indicates a combination system.
4. What is the purpose of a ‘Cope’s Regulator’ in a high-pressure steam plant?
A. To regulate fuel oil pressure
B. To monitor carbon monoxide levels
C. To adjust the stack draft
, D. To control the feedwater level automatically
Answer: D
Conceptual Explanation: A Cope’s regulator is a mechanical device used to maintain a
consistent water level in the boiler by regulating feedwater flow.
5. When performing a hydrostatic test on a boiler, the pressure should typically be raised to
what percentage of the Maximum Allowable Working Pressure (MAWP)?
A. 150%
B. 125%
C. 100%
D. 200%
Answer: A
Conceptual Explanation: ASME and NYC codes generally require hydrostatic tests to be
conducted at 1.5 times (150%) the MAWP.
6. In a centrifugal pump, what is the term for the formation of vapor bubbles in low-pressure
areas that collapse violently?
A. Priming
B. Cavitation
C. Surging
D. Water Hammer
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS
1. In a low-pressure steam boiler, what is the primary cause of ‘foaming’ which leads to
inaccurate water level readings?
A. High concentration of dissolved solids and oils
B. Low concentration of dissolved solids
C. Excessive boiler blowdown
D. Insufficient fuel oil atomization
Answer: A
Conceptual Explanation: Foaming is caused by a high concentration of dissolved solids,
organics, or oils on the surface of the boiler water, which prevents steam bubbles from
breaking freely.
2. Which type of steam trap uses a corrugated bellows filled with a volatile liquid to open and
close based on temperature?
A. Inverted bucket trap
B. Float and thermostatic trap
,C. Thermostatic trap
D. Thermodynamic disc trap
Answer: C
Conceptual Explanation: Thermostatic traps operate on the principle of temperature
difference using a bellows or bimetallic element.
3. According to NYC FDNY regulations, what color must the caps of a standpipe system’s
Siamese connection be?
A. Yellow
B. Green
C. Red
D. Silver
Answer: C
Conceptual Explanation: Red caps indicate a standpipe system; green indicates a
sprinkler system; yellow indicates a combination system.
4. What is the purpose of a ‘Cope’s Regulator’ in a high-pressure steam plant?
A. To regulate fuel oil pressure
B. To monitor carbon monoxide levels
C. To adjust the stack draft
, D. To control the feedwater level automatically
Answer: D
Conceptual Explanation: A Cope’s regulator is a mechanical device used to maintain a
consistent water level in the boiler by regulating feedwater flow.
5. When performing a hydrostatic test on a boiler, the pressure should typically be raised to
what percentage of the Maximum Allowable Working Pressure (MAWP)?
A. 150%
B. 125%
C. 100%
D. 200%
Answer: A
Conceptual Explanation: ASME and NYC codes generally require hydrostatic tests to be
conducted at 1.5 times (150%) the MAWP.
6. In a centrifugal pump, what is the term for the formation of vapor bubbles in low-pressure
areas that collapse violently?
A. Priming
B. Cavitation
C. Surging
D. Water Hammer
