NYC Health + Hospitals Senior Air
Conditioning Mechanic Examination
Practice Exam 2026 | 100 Questions &
Answers with Detailed Rationales |
Complete Exam Prep & Study Guide
1. What is the primary function of an air-conditioning compressor?
A. Remove moisture from air
B. Circulate refrigerant and raise its pressure
C. Reduce condenser pressure
D. Filter contaminants from refrigerant
Answer: Circulate refrigerant and raise its pressure
Rationale: The compressor draws low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, high-temperature vapor for
delivery to the condenser.
2. Which component removes heat from the conditioned space?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: Evaporator
,Rationale: The evaporator absorbs heat from indoor air as refrigerant changes
from a low-pressure liquid/vapor mixture into vapor.
3. What is the main purpose of the condenser?
A. Absorb indoor heat
B. Reject heat from the refrigerant
C. Increase evaporator pressure
D. Meter refrigerant flow
Answer: Reject heat from the refrigerant
Rationale: The condenser removes heat from the hot discharge gas, allowing the
refrigerant to condense into a liquid.
4. Which device meters refrigerant entering an evaporator?
A. Compressor
B. Condenser fan
C. Expansion valve
D. Accumulator
Answer: Expansion valve
Rationale: An expansion valve controls refrigerant flow and reduces its pressure
before it enters the evaporator.
5. What happens to refrigerant pressure across an expansion valve?
A. It increases
B. It remains constant
C. It decreases
D. It becomes atmospheric
Answer: It decreases
Rationale: The expansion device creates a pressure drop that produces a low-
pressure refrigerant mixture suitable for evaporation.
, 6. What does superheat represent?
A. Temperature of liquid above its freezing point
B. Temperature of vapor above its saturation temperature
C. Condenser temperature below ambient
D. Compressor oil temperature
Answer: Temperature of vapor above its saturation temperature
Rationale: Superheat indicates how much a vapor has been heated above its
saturation temperature at a given pressure.
7. What does subcooling indicate?
A. Vapor below saturation temperature
B. Liquid below its saturation temperature
C. Compressor temperature above normal
D. Air temperature below freezing
Answer: Liquid below its saturation temperature
Rationale: Subcooling is the temperature difference between the refrigerant's
saturation temperature and the actual liquid temperature.
8. What is the purpose of a filter-drier in a refrigeration system?
A. Increase compressor speed
B. Remove moisture and contaminants
C. Increase suction pressure
D. Reduce airflow
Answer: Remove moisture and contaminants
Rationale: Filter-driers protect the refrigeration system by trapping debris and
absorbing moisture that could damage components.
9. What is the purpose of an accumulator?
, A. Store compressor oil permanently
B. Prevent liquid refrigerant from entering the compressor
C. Increase condenser airflow
D. Meter refrigerant into the evaporator
Answer: Prevent liquid refrigerant from entering the compressor
Rationale: A suction accumulator can temporarily hold liquid refrigerant and
help protect the compressor from liquid slugging.
10.Which condition can cause liquid refrigerant to enter a compressor?
A. Excessive superheat
B. Floodback
C. Proper subcooling
D. Low airflow only
Answer: Floodback
Rationale: Floodback occurs when liquid refrigerant returns through the suction
line to the compressor, potentially causing severe mechanical damage.
11.What is compressor slugging?
A. Excessive airflow through the evaporator
B. Liquid entering the compressor cylinders
C. High condenser airflow
D. Refrigerant leakage through the condenser
Answer: Liquid entering the compressor cylinders
Rationale: Compressors are designed to compress vapor, not liquid. Liquid
slugging can bend rods, damage valves, and destroy the compressor.
12.What instrument is commonly used to measure refrigerant pressure?
A. Psychrometer
B. Manifold gauge set
Conditioning Mechanic Examination
Practice Exam 2026 | 100 Questions &
Answers with Detailed Rationales |
Complete Exam Prep & Study Guide
1. What is the primary function of an air-conditioning compressor?
A. Remove moisture from air
B. Circulate refrigerant and raise its pressure
C. Reduce condenser pressure
D. Filter contaminants from refrigerant
Answer: Circulate refrigerant and raise its pressure
Rationale: The compressor draws low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, high-temperature vapor for
delivery to the condenser.
2. Which component removes heat from the conditioned space?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: Evaporator
,Rationale: The evaporator absorbs heat from indoor air as refrigerant changes
from a low-pressure liquid/vapor mixture into vapor.
3. What is the main purpose of the condenser?
A. Absorb indoor heat
B. Reject heat from the refrigerant
C. Increase evaporator pressure
D. Meter refrigerant flow
Answer: Reject heat from the refrigerant
Rationale: The condenser removes heat from the hot discharge gas, allowing the
refrigerant to condense into a liquid.
4. Which device meters refrigerant entering an evaporator?
A. Compressor
B. Condenser fan
C. Expansion valve
D. Accumulator
Answer: Expansion valve
Rationale: An expansion valve controls refrigerant flow and reduces its pressure
before it enters the evaporator.
5. What happens to refrigerant pressure across an expansion valve?
A. It increases
B. It remains constant
C. It decreases
D. It becomes atmospheric
Answer: It decreases
Rationale: The expansion device creates a pressure drop that produces a low-
pressure refrigerant mixture suitable for evaporation.
, 6. What does superheat represent?
A. Temperature of liquid above its freezing point
B. Temperature of vapor above its saturation temperature
C. Condenser temperature below ambient
D. Compressor oil temperature
Answer: Temperature of vapor above its saturation temperature
Rationale: Superheat indicates how much a vapor has been heated above its
saturation temperature at a given pressure.
7. What does subcooling indicate?
A. Vapor below saturation temperature
B. Liquid below its saturation temperature
C. Compressor temperature above normal
D. Air temperature below freezing
Answer: Liquid below its saturation temperature
Rationale: Subcooling is the temperature difference between the refrigerant's
saturation temperature and the actual liquid temperature.
8. What is the purpose of a filter-drier in a refrigeration system?
A. Increase compressor speed
B. Remove moisture and contaminants
C. Increase suction pressure
D. Reduce airflow
Answer: Remove moisture and contaminants
Rationale: Filter-driers protect the refrigeration system by trapping debris and
absorbing moisture that could damage components.
9. What is the purpose of an accumulator?
, A. Store compressor oil permanently
B. Prevent liquid refrigerant from entering the compressor
C. Increase condenser airflow
D. Meter refrigerant into the evaporator
Answer: Prevent liquid refrigerant from entering the compressor
Rationale: A suction accumulator can temporarily hold liquid refrigerant and
help protect the compressor from liquid slugging.
10.Which condition can cause liquid refrigerant to enter a compressor?
A. Excessive superheat
B. Floodback
C. Proper subcooling
D. Low airflow only
Answer: Floodback
Rationale: Floodback occurs when liquid refrigerant returns through the suction
line to the compressor, potentially causing severe mechanical damage.
11.What is compressor slugging?
A. Excessive airflow through the evaporator
B. Liquid entering the compressor cylinders
C. High condenser airflow
D. Refrigerant leakage through the condenser
Answer: Liquid entering the compressor cylinders
Rationale: Compressors are designed to compress vapor, not liquid. Liquid
slugging can bend rods, damage valves, and destroy the compressor.
12.What instrument is commonly used to measure refrigerant pressure?
A. Psychrometer
B. Manifold gauge set
