NYC CUSTODIAN ENGINEER
EXAMINATION PRACTICE TEST
QUESTIONS AND ANSWERS
1. What is the primary function of a Hartford Loop in a steam boiler system?
A. To allow for thermal expansion of the condensate return piping
B. To increase the pressure of the steam leaving the boiler
C. To separate air from the steam in the supply header
D. To prevent boiler water from flowing back into the return line if a leak occurs
Answer: D
Conceptual Explanation: The Hartford Loop is a piping arrangement that prevents the
boiler water level from dropping below the lowest safe water level in the event of a leak in
the return line.
2. According to the NYC Building Code, what color should the handles of fire standpipe valves
be painted?
A. Yellow
B. Green
,C. Silver
D. Red
Answer: D
Conceptual Explanation: In New York City, standpipe system components, including valve
handles, must be painted red to ensure visibility for the fire department.
3. Which condition is most likely to cause ‘foaming’ in a steam boiler?
A. Operating the boiler at a pressure higher than its design limit
B. Excessive concentrations of dissolved solids or oil in the boiler water
C. A malfunctioning low-water cut-off
D. Too much oxygen in the feed water
Answer: B
Conceptual Explanation: Foaming is caused by high surface tension resulting from
impurities like oil, grease, or high concentrations of dissolved solids, preventing steam
bubbles from breaking freely.
4. In a refrigeration system, where is the refrigerant at its highest pressure and temperature?
A. At the compressor discharge
B. In the evaporator
C. Between the expansion valve and the evaporator
, D. In the suction line
Answer: A
Conceptual Explanation: The compressor increases both the pressure and temperature of
the refrigerant vapor; therefore, the highest values are found at the discharge side before it
enters the condenser.
5. A ‘Slow Opening’ valve on a boiler blowdown line is defined as a valve that requires how
many full turns to open or close?
A. At least two full turns
B. Exactly three full turns
C. At least five full turns
D. More than ten full turns
Answer: C
Conceptual Explanation: Safety codes define a slow-opening valve as one that requires at
least five full 360-degree turns of the operating mechanism to go from fully closed to fully
open.
6. Which type of steam trap operates based on the difference in density between steam and
condensate?
A. Thermostatic trap
B. Thermodynamic (disc) trap
EXAMINATION PRACTICE TEST
QUESTIONS AND ANSWERS
1. What is the primary function of a Hartford Loop in a steam boiler system?
A. To allow for thermal expansion of the condensate return piping
B. To increase the pressure of the steam leaving the boiler
C. To separate air from the steam in the supply header
D. To prevent boiler water from flowing back into the return line if a leak occurs
Answer: D
Conceptual Explanation: The Hartford Loop is a piping arrangement that prevents the
boiler water level from dropping below the lowest safe water level in the event of a leak in
the return line.
2. According to the NYC Building Code, what color should the handles of fire standpipe valves
be painted?
A. Yellow
B. Green
,C. Silver
D. Red
Answer: D
Conceptual Explanation: In New York City, standpipe system components, including valve
handles, must be painted red to ensure visibility for the fire department.
3. Which condition is most likely to cause ‘foaming’ in a steam boiler?
A. Operating the boiler at a pressure higher than its design limit
B. Excessive concentrations of dissolved solids or oil in the boiler water
C. A malfunctioning low-water cut-off
D. Too much oxygen in the feed water
Answer: B
Conceptual Explanation: Foaming is caused by high surface tension resulting from
impurities like oil, grease, or high concentrations of dissolved solids, preventing steam
bubbles from breaking freely.
4. In a refrigeration system, where is the refrigerant at its highest pressure and temperature?
A. At the compressor discharge
B. In the evaporator
C. Between the expansion valve and the evaporator
, D. In the suction line
Answer: A
Conceptual Explanation: The compressor increases both the pressure and temperature of
the refrigerant vapor; therefore, the highest values are found at the discharge side before it
enters the condenser.
5. A ‘Slow Opening’ valve on a boiler blowdown line is defined as a valve that requires how
many full turns to open or close?
A. At least two full turns
B. Exactly three full turns
C. At least five full turns
D. More than ten full turns
Answer: C
Conceptual Explanation: Safety codes define a slow-opening valve as one that requires at
least five full 360-degree turns of the operating mechanism to go from fully closed to fully
open.
6. Which type of steam trap operates based on the difference in density between steam and
condensate?
A. Thermostatic trap
B. Thermodynamic (disc) trap
