NYC CUSTODIAN ENGINEER
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS
1. What is the primary purpose of a Hartford Loop in a low-pressure steam heating system?
A. To serve as a secondary safety valve for pressure relief
B. To increase the velocity of the steam returning to the boiler
C. To prevent water from leaving the boiler in the event of a return line leak
D. To allow for thermal expansion of the main steam header
Answer: C
Conceptual Explanation: The Hartford Loop is a piping arrangement designed to prevent
water from being pushed out of the boiler if a leak develops in the return line, thereby
protecting the boiler from a dry-fire condition.
2. In a centrifugal pump, what is the most likely cause of cavitation?
A. Operating the pump at too low a speed
B. Excessive discharge pressure
C. Insufficient Net Positive Suction Head (NPSH)
,D. Air leaking into the stuffing box
Answer: C
Conceptual Explanation: Cavitation occurs when the pressure at the pump suction drops
below the vapor pressure of the liquid, causing bubbles to form and then collapse violently.
3. According to NYC Department of Buildings (DOB) regulations, how often must a low-
pressure boiler undergo an external inspection?
A. Every two years
B. Annually
C. Every three years
D. Semi-annually
Answer: B
Conceptual Explanation: NYC DOB requires annual inspections for boilers to ensure
safety and compliance with the building code.
4. Which type of steam trap is most susceptible to damage from water hammer?
A. Thermostatic trap
B. Float and thermostatic trap
C. Inverted bucket trap
D. Thermodynamic trap
, Answer: B
Conceptual Explanation: Float and thermostatic (F&T) traps are sensitive to water
hammer because the float can be crushed by the impact of water slugs.
5. What is the function of a ‘Sacrificial Anode’ in a domestic hot water storage tank?
A. To prevent corrosion of the tank walls via electrolysis
B. To improve the taste of the water
C. To heat the water during peak demand
D. To filter out sediments from the water supply
Answer: A
Conceptual Explanation: A sacrificial anode (usually magnesium or aluminum) corrodes
faster than the steel tank, thereby protecting the tank from galvanic corrosion.
6. A ‘Class K’ fire extinguisher is specifically designed for which type of hazard?
A. Commercial cooking oils and fats
B. Combustible metals
C. Flammable liquids
D. Electrical equipment
Answer: A
COMPREHENSIVE EXAM QUESTIONS
AND ANSWERS
1. What is the primary purpose of a Hartford Loop in a low-pressure steam heating system?
A. To serve as a secondary safety valve for pressure relief
B. To increase the velocity of the steam returning to the boiler
C. To prevent water from leaving the boiler in the event of a return line leak
D. To allow for thermal expansion of the main steam header
Answer: C
Conceptual Explanation: The Hartford Loop is a piping arrangement designed to prevent
water from being pushed out of the boiler if a leak develops in the return line, thereby
protecting the boiler from a dry-fire condition.
2. In a centrifugal pump, what is the most likely cause of cavitation?
A. Operating the pump at too low a speed
B. Excessive discharge pressure
C. Insufficient Net Positive Suction Head (NPSH)
,D. Air leaking into the stuffing box
Answer: C
Conceptual Explanation: Cavitation occurs when the pressure at the pump suction drops
below the vapor pressure of the liquid, causing bubbles to form and then collapse violently.
3. According to NYC Department of Buildings (DOB) regulations, how often must a low-
pressure boiler undergo an external inspection?
A. Every two years
B. Annually
C. Every three years
D. Semi-annually
Answer: B
Conceptual Explanation: NYC DOB requires annual inspections for boilers to ensure
safety and compliance with the building code.
4. Which type of steam trap is most susceptible to damage from water hammer?
A. Thermostatic trap
B. Float and thermostatic trap
C. Inverted bucket trap
D. Thermodynamic trap
, Answer: B
Conceptual Explanation: Float and thermostatic (F&T) traps are sensitive to water
hammer because the float can be crushed by the impact of water slugs.
5. What is the function of a ‘Sacrificial Anode’ in a domestic hot water storage tank?
A. To prevent corrosion of the tank walls via electrolysis
B. To improve the taste of the water
C. To heat the water during peak demand
D. To filter out sediments from the water supply
Answer: A
Conceptual Explanation: A sacrificial anode (usually magnesium or aluminum) corrodes
faster than the steel tank, thereby protecting the tank from galvanic corrosion.
6. A ‘Class K’ fire extinguisher is specifically designed for which type of hazard?
A. Commercial cooking oils and fats
B. Combustible metals
C. Flammable liquids
D. Electrical equipment
Answer: A
