FDNY Refrigeration Exam
FDNY REFRIGERATION EXAM PRACTICE
Practice Test
TEST |100% CORRECT QUESTIONS WITH
100% CORRECT ANSWERS |2026 UPLOAD
|100% CORRECT
1. Several methods are used to improve the efficiency of refrigeration
systems. It is common to utilize two stages of compression with cooling
between the stages. This improves efficiency by:
keeping the compression closer to the ideal isenthalpic path to
reduce compression power
keeping the compression closer to the ideal isentropic path to
reduce compression power
reducing condenser cooling
increasing the propane compressor discharge temperature
increasing the amount of cooling per kg of propane
2. Describe the process that allows a refrigerant to become superheated in
the refrigeration cycle.
The refrigerant expands in the expansion valve, causing it to cool
down.
The refrigerant is compressed in the compressor, increasing its
pressure and temperature.
The refrigerant absorbs heat in the evaporator, raising its
temperature above its boiling point.
The refrigerant releases heat in the condenser, causing it to cool
down.
3. What is the primary factor that can lead to cavitation in a condenser water
,pump?
Low suction pressure
Inadequate cooling water supply
, High discharge pressure
Excessive flow rate
4. If a refrigeration system using R-123 experiences a drop in efficiency, what
could be a potential cause related to the in-line refrigerant cleaning
system?
Contamination in the refrigerant due to a malfunctioning cleaning
system.
Inadequate insulation on the refrigerant lines.
Excessive refrigerant charge in the system.
Improper compressor sizing for the application.
5. Describe the role of a TXV in maintaining system efficiency in refrigeration.
The TXV monitors the overall energy consumption of the
refrigeration system.
The TXV regulates the flow of refrigerant to maintain a constant
superheat, ensuring efficient operation.
The TXV controls the pressure of the refrigerant to prevent system
overload.
The TXV adjusts the temperature of the refrigerant to enhance
cooling capacity.
6. What is the primary function of an equalizer line in a thermal expansion
valve (TXV)?
To equalize pressure between the sensing bulb and the
evaporator.
To increase refrigerant flow to the compressor.
To regulate the temperature of the refrigerant.
To prevent refrigerant leaks.
, 7. Non-condensable gases like air, oil vapor, or nitrogen travel through a
refrigerant system with the refrigerant they usually accumulate in the:
Condenser
Evaporator
Filter drier
Compressor crankcase
8. In a refrigeration system experiencing frequent frost buildup on the
evaporator coils, which component would be most effective to install to
improve efficiency?
Condenser fans
Thermostatic expansion valves
Refrigerant compressors
Defrosting heaters
9. Describe how the pressure ratio in a centrifugal compressor affects its
efficiency and performance.
Pressure ratio has no effect on the efficiency of a centrifugal
compressor.
A lower pressure ratio indicates better efficiency because it requires
less energy to compress the refrigerant.
A higher pressure ratio typically indicates greater efficiency and
performance in a centrifugal compressor, as it signifies a larger
difference between suction and discharge pressures.
The pressure ratio only affects the temperature of the refrigerant,
not the efficiency.
10. What is one key advantage of glycol over salt brine in refrigeration
systems?
FDNY REFRIGERATION EXAM PRACTICE
Practice Test
TEST |100% CORRECT QUESTIONS WITH
100% CORRECT ANSWERS |2026 UPLOAD
|100% CORRECT
1. Several methods are used to improve the efficiency of refrigeration
systems. It is common to utilize two stages of compression with cooling
between the stages. This improves efficiency by:
keeping the compression closer to the ideal isenthalpic path to
reduce compression power
keeping the compression closer to the ideal isentropic path to
reduce compression power
reducing condenser cooling
increasing the propane compressor discharge temperature
increasing the amount of cooling per kg of propane
2. Describe the process that allows a refrigerant to become superheated in
the refrigeration cycle.
The refrigerant expands in the expansion valve, causing it to cool
down.
The refrigerant is compressed in the compressor, increasing its
pressure and temperature.
The refrigerant absorbs heat in the evaporator, raising its
temperature above its boiling point.
The refrigerant releases heat in the condenser, causing it to cool
down.
3. What is the primary factor that can lead to cavitation in a condenser water
,pump?
Low suction pressure
Inadequate cooling water supply
, High discharge pressure
Excessive flow rate
4. If a refrigeration system using R-123 experiences a drop in efficiency, what
could be a potential cause related to the in-line refrigerant cleaning
system?
Contamination in the refrigerant due to a malfunctioning cleaning
system.
Inadequate insulation on the refrigerant lines.
Excessive refrigerant charge in the system.
Improper compressor sizing for the application.
5. Describe the role of a TXV in maintaining system efficiency in refrigeration.
The TXV monitors the overall energy consumption of the
refrigeration system.
The TXV regulates the flow of refrigerant to maintain a constant
superheat, ensuring efficient operation.
The TXV controls the pressure of the refrigerant to prevent system
overload.
The TXV adjusts the temperature of the refrigerant to enhance
cooling capacity.
6. What is the primary function of an equalizer line in a thermal expansion
valve (TXV)?
To equalize pressure between the sensing bulb and the
evaporator.
To increase refrigerant flow to the compressor.
To regulate the temperature of the refrigerant.
To prevent refrigerant leaks.
, 7. Non-condensable gases like air, oil vapor, or nitrogen travel through a
refrigerant system with the refrigerant they usually accumulate in the:
Condenser
Evaporator
Filter drier
Compressor crankcase
8. In a refrigeration system experiencing frequent frost buildup on the
evaporator coils, which component would be most effective to install to
improve efficiency?
Condenser fans
Thermostatic expansion valves
Refrigerant compressors
Defrosting heaters
9. Describe how the pressure ratio in a centrifugal compressor affects its
efficiency and performance.
Pressure ratio has no effect on the efficiency of a centrifugal
compressor.
A lower pressure ratio indicates better efficiency because it requires
less energy to compress the refrigerant.
A higher pressure ratio typically indicates greater efficiency and
performance in a centrifugal compressor, as it signifies a larger
difference between suction and discharge pressures.
The pressure ratio only affects the temperature of the refrigerant,
not the efficiency.
10. What is one key advantage of glycol over salt brine in refrigeration
systems?
