NYC Health Hospitals Air Conditioning
Mechanic Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
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1. In a hospital air conditioning system, a technician is troubleshooting a
chilled-water air handling unit that is producing warm supply air. The
chilled-water valve is open, the pump is operating, and the fan is
running normally. The technician measures a very small temperature
difference between chilled-water supply and return lines. Which
condition is the MOST likely cause of poor cooling performance?
A. Excessive airflow across the coil
B. Dirty or fouled evaporator coil restricting heat transfer
C. Incorrect rotation of the supply fan motor
D. Overheated condenser motor windings
Answer: B. Dirty or fouled evaporator coil restricting heat transfer
,A restricted or dirty coil reduces the ability of refrigerant or chilled water to
absorb heat, causing poor temperature transfer and a reduced
temperature difference across the coil.
2. A hospital air conditioning mechanic is performing preventive
maintenance on a variable air volume (VAV) system. The mechanic
notices that several terminal boxes are not maintaining room
temperature even though the air handling unit is operating correctly.
Which component should be inspected first?
A. VAV damper actuator and airflow sensor
B. Compressor crankcase heater
C. Condenser fan blade pitch
D. Refrigerant receiver level
Answer: A. VAV damper actuator and airflow sensor
VAV systems regulate room conditions by adjusting airflow through
dampers controlled by actuators and sensors; failures in these components
commonly cause incorrect space temperatures.
3. A refrigeration circuit in a hospital split air conditioning system shows
high suction pressure and low superheat. What is the most likely
cause?
A. Refrigerant undercharge
B. Restricted airflow over the evaporator
,C. Overfeeding of refrigerant into the evaporator
D. Blocked condenser coil
Answer: C. Overfeeding of refrigerant into the evaporator
Excess refrigerant entering the evaporator causes incomplete vaporization,
resulting in low superheat and elevated suction pressure.
4. Before servicing electrical components of an air conditioning unit in a
healthcare facility, the mechanic must follow lockout/tagout
procedures. The primary purpose of lockout/tagout is to:
A. Increase equipment operating efficiency
B. Prevent unexpected energization of equipment during maintenance
C. Reduce refrigerant pressure
D. Improve thermostat calibration
Answer: B. Prevent unexpected energization of equipment during
maintenance
Lockout/tagout protects workers by ensuring equipment cannot
accidentally start or become energized while maintenance work is being
performed.
5. A technician is charging a refrigeration system using a cylinder of
blended refrigerant. Why must the refrigerant generally be removed
from the cylinder as a liquid during charging?
, A. Liquid refrigerant improves compressor lubrication
B. Vapor charging changes the refrigerant composition of blends
C. Liquid charging prevents all leaks
D. Vapor charging increases system capacity
Answer: B. Vapor charging changes the refrigerant composition of blends
Many blended refrigerants contain multiple components that can separate;
charging as vapor may alter the refrigerant mixture and reduce system
performance.
6. A hospital operating room requires positive pressure relative to
surrounding areas. The HVAC mechanic understands that maintaining
positive pressure requires:
A. Exhaust airflow greater than supply airflow
B. Supply airflow greater than exhaust airflow
C. Closing all return air openings
D. Eliminating outside air intake
Answer: B. Supply airflow greater than exhaust airflow
Positive pressure rooms maintain higher pressure by supplying more
conditioned air than is exhausted, preventing contaminants from entering
the space.
7. When measuring superheat on a refrigeration system, the mechanic
should compare:
Mechanic Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. In a hospital air conditioning system, a technician is troubleshooting a
chilled-water air handling unit that is producing warm supply air. The
chilled-water valve is open, the pump is operating, and the fan is
running normally. The technician measures a very small temperature
difference between chilled-water supply and return lines. Which
condition is the MOST likely cause of poor cooling performance?
A. Excessive airflow across the coil
B. Dirty or fouled evaporator coil restricting heat transfer
C. Incorrect rotation of the supply fan motor
D. Overheated condenser motor windings
Answer: B. Dirty or fouled evaporator coil restricting heat transfer
,A restricted or dirty coil reduces the ability of refrigerant or chilled water to
absorb heat, causing poor temperature transfer and a reduced
temperature difference across the coil.
2. A hospital air conditioning mechanic is performing preventive
maintenance on a variable air volume (VAV) system. The mechanic
notices that several terminal boxes are not maintaining room
temperature even though the air handling unit is operating correctly.
Which component should be inspected first?
A. VAV damper actuator and airflow sensor
B. Compressor crankcase heater
C. Condenser fan blade pitch
D. Refrigerant receiver level
Answer: A. VAV damper actuator and airflow sensor
VAV systems regulate room conditions by adjusting airflow through
dampers controlled by actuators and sensors; failures in these components
commonly cause incorrect space temperatures.
3. A refrigeration circuit in a hospital split air conditioning system shows
high suction pressure and low superheat. What is the most likely
cause?
A. Refrigerant undercharge
B. Restricted airflow over the evaporator
,C. Overfeeding of refrigerant into the evaporator
D. Blocked condenser coil
Answer: C. Overfeeding of refrigerant into the evaporator
Excess refrigerant entering the evaporator causes incomplete vaporization,
resulting in low superheat and elevated suction pressure.
4. Before servicing electrical components of an air conditioning unit in a
healthcare facility, the mechanic must follow lockout/tagout
procedures. The primary purpose of lockout/tagout is to:
A. Increase equipment operating efficiency
B. Prevent unexpected energization of equipment during maintenance
C. Reduce refrigerant pressure
D. Improve thermostat calibration
Answer: B. Prevent unexpected energization of equipment during
maintenance
Lockout/tagout protects workers by ensuring equipment cannot
accidentally start or become energized while maintenance work is being
performed.
5. A technician is charging a refrigeration system using a cylinder of
blended refrigerant. Why must the refrigerant generally be removed
from the cylinder as a liquid during charging?
, A. Liquid refrigerant improves compressor lubrication
B. Vapor charging changes the refrigerant composition of blends
C. Liquid charging prevents all leaks
D. Vapor charging increases system capacity
Answer: B. Vapor charging changes the refrigerant composition of blends
Many blended refrigerants contain multiple components that can separate;
charging as vapor may alter the refrigerant mixture and reduce system
performance.
6. A hospital operating room requires positive pressure relative to
surrounding areas. The HVAC mechanic understands that maintaining
positive pressure requires:
A. Exhaust airflow greater than supply airflow
B. Supply airflow greater than exhaust airflow
C. Closing all return air openings
D. Eliminating outside air intake
Answer: B. Supply airflow greater than exhaust airflow
Positive pressure rooms maintain higher pressure by supplying more
conditioned air than is exhausted, preventing contaminants from entering
the space.
7. When measuring superheat on a refrigeration system, the mechanic
should compare:
