FDNY Z51/ Z-51 REFRIGERATION
FINAL EXAM PREP 2025/2026
ACCURATE QUESTIONS WITH
CORRECT DETAILED ANSWERS ||
100% GUARANTEED PASS
<LATEST VERSION>
1. A refrigerant engineer verifies that a condenser pump is cavitating of the
following the most likely cause for this condition is: - ANSWER ✓ a faulty
cooling tower water level controller
2. When an expansion valve is operating properly, at the end of the evaporator
will contain - ANSWER ✓ only superheated vapor
3. A centrifugal water pump is considered to be fully primed when - ANSWER
✓ the pump is full of liquid
4. A refrigeration compressor has failed to turn on. the engineer on duty
verifies the electrical circuit to the motor, including all switches and circuit
breakers is complete, according to recomended service practice, the next
item to be checked would likely be the: - ANSWER ✓ temperature and
pressure controls
5. The amount of refrigerant that flows through the orifices of an economizer is
Determined by the - ANSWER ✓ Difference between the high side in low
side pressure
,6. The installation of an inline refrigerate cleaning system is Adviseable -
ANSWER ✓ To remove impurities from the system
7. The type of refrigerant system that is least likely to leak refrigerant into the
building space that a being cooled are - ANSWER ✓ An indirect system
8. A superheated vapor is - ANSWER ✓ Dry vapor above the saturation
temperature
9. A Centrifugal water pump is known as a lift pump when the - ANSWER ✓
The water supply to the pump suction inlet is below the pump level
10.A TXV is used to maintain constant - ANSWER ✓ Evaporator superheat
11.In a steam turbine what is the function of the Kingsbury thrust bearing -
ANSWER ✓ Maintains axial position of the rotor shaft
12.Copper tubing refrigerant lines must be installed for a new system it is a well
known service practice that tubing collapses At Bendd that must be made the
refrigerant engineer should use - ANSWER ✓ A lever type tubing Bender
13.A low side float is used to maintain: - ANSWER ✓ The Level of refrigerant
inside the evaporator
14.Or reciprocating compressor is making a knocking sound during operation if
parts are not the cause of the knocking - ANSWER ✓ Slugging of the liquid
refrigerant
15.In order for for drink to become superheated and must be heated in a section
of the low side refrigerant line - ANSWER ✓ Were no liquid Refrigerant is
present
16.All liquid has been recovered from a system to be overhauled the system -
ANSWER ✓ Should not be opened until all vapor has been recovered
17.What is the function of the turbine auxiliary oil pump - ANSWER ✓
Establish oil pressure doing turbine start up
,18.The ruptured disk for a low pressure centrifugal refrigeration machine is
normally located on the - ANSWER ✓ Compressor suction
19.What is the primary reason ribbed metal piping is used for electrical wires
connected to the refrigeration system shown below - ANSWER ✓ It allows
for flexibility and accounts for vibrations
20.A multi cylinder reciprocating compressor uses cylinder unloaders to
regularly capacity what would not occur if some of the unloaders fail to
operate when needed - ANSWER ✓ The chill water temperature will
increase
21.Of the following centrifugal refrigeration machine his best characterized by -
ANSWER ✓ High volume low pressure machine
22.Modern compresses usually sealed the rotating shaft as it exit the
compressor housing a Spring loaded seal made of - ANSWER ✓ Metal or
carbon
23.The British thermal unit BTU is a measurement of heat of energy if 10 be to
you a transfer to 10 pounds of water the water temperature increase will be
closest to - ANSWER ✓ 1ﾟF
24.The Flash point of compressor lubricating oil - ANSWER ✓ Should be
higher than the compression temperature
25.The most common reason for refrigeration engineer to use a psychrommeter
is to measure - ANSWER ✓ Relatively humidity level of the atmosphere
26.Under normal conditions the refrigerant enters the Compressor as a -
ANSWER ✓ Low pressure superheated vapor and leaves as a high pressure
of vapor
27.What is the function of the vacuum breaker in a steam turbine - ANSWER ✓
To achieve a faster coast down cycle
28.An equalizer line on TXV is used for - ANSWER ✓ Compensate for the
pressure drop across the evaporator coil
, 29.In a multistage and a typical compressor each stage Is - ANSWER ✓
Identicle in volume to the other stages
30.In relation to the suction pressure of a compressor the reading of the oil
pressure gauge should read in a range closer to - ANSWER ✓ 15 to 30 PSI
above the suction pressure
31.A condenser pump is supplied with 85 degree water from a cooling tower
and returns to the tower at 88 degrees Engineer is sure the condenser tubes
are clean and free of obstructions. The condenser has high condenser
pressure. The reason for this could be? - ANSWER ✓ Overcharge of
refrigerant
32.What is the lowest temperature a cooling tower can be? - ANSWER ✓ Wet
bulb temperature
33.Manifold hoses should be equipped with? - ANSWER ✓ Low loss fittings
34.Water regulating valves are used to? - ANSWER ✓ Maintain condenser
pressure to a pre-determined level
35.You are the only engineer on duty with a machine running. A vice president
tells you to shovel snow. What should you do? - ANSWER ✓ Do not leave
building
36.How often must you do emergency power testing? - ANSWER ✓ Monthly
37.What is the responsibility of a B29 COF holder? - ANSWER ✓ Inspect the
battery system
38.Why is a refrigerant gauge called a compound gauge? - ANSWER ✓ It reads
positive pressure and vacuum
39.Which of the following does not require flame resistant treatment? -
ANSWER ✓ Art work in a museum
FINAL EXAM PREP 2025/2026
ACCURATE QUESTIONS WITH
CORRECT DETAILED ANSWERS ||
100% GUARANTEED PASS
<LATEST VERSION>
1. A refrigerant engineer verifies that a condenser pump is cavitating of the
following the most likely cause for this condition is: - ANSWER ✓ a faulty
cooling tower water level controller
2. When an expansion valve is operating properly, at the end of the evaporator
will contain - ANSWER ✓ only superheated vapor
3. A centrifugal water pump is considered to be fully primed when - ANSWER
✓ the pump is full of liquid
4. A refrigeration compressor has failed to turn on. the engineer on duty
verifies the electrical circuit to the motor, including all switches and circuit
breakers is complete, according to recomended service practice, the next
item to be checked would likely be the: - ANSWER ✓ temperature and
pressure controls
5. The amount of refrigerant that flows through the orifices of an economizer is
Determined by the - ANSWER ✓ Difference between the high side in low
side pressure
,6. The installation of an inline refrigerate cleaning system is Adviseable -
ANSWER ✓ To remove impurities from the system
7. The type of refrigerant system that is least likely to leak refrigerant into the
building space that a being cooled are - ANSWER ✓ An indirect system
8. A superheated vapor is - ANSWER ✓ Dry vapor above the saturation
temperature
9. A Centrifugal water pump is known as a lift pump when the - ANSWER ✓
The water supply to the pump suction inlet is below the pump level
10.A TXV is used to maintain constant - ANSWER ✓ Evaporator superheat
11.In a steam turbine what is the function of the Kingsbury thrust bearing -
ANSWER ✓ Maintains axial position of the rotor shaft
12.Copper tubing refrigerant lines must be installed for a new system it is a well
known service practice that tubing collapses At Bendd that must be made the
refrigerant engineer should use - ANSWER ✓ A lever type tubing Bender
13.A low side float is used to maintain: - ANSWER ✓ The Level of refrigerant
inside the evaporator
14.Or reciprocating compressor is making a knocking sound during operation if
parts are not the cause of the knocking - ANSWER ✓ Slugging of the liquid
refrigerant
15.In order for for drink to become superheated and must be heated in a section
of the low side refrigerant line - ANSWER ✓ Were no liquid Refrigerant is
present
16.All liquid has been recovered from a system to be overhauled the system -
ANSWER ✓ Should not be opened until all vapor has been recovered
17.What is the function of the turbine auxiliary oil pump - ANSWER ✓
Establish oil pressure doing turbine start up
,18.The ruptured disk for a low pressure centrifugal refrigeration machine is
normally located on the - ANSWER ✓ Compressor suction
19.What is the primary reason ribbed metal piping is used for electrical wires
connected to the refrigeration system shown below - ANSWER ✓ It allows
for flexibility and accounts for vibrations
20.A multi cylinder reciprocating compressor uses cylinder unloaders to
regularly capacity what would not occur if some of the unloaders fail to
operate when needed - ANSWER ✓ The chill water temperature will
increase
21.Of the following centrifugal refrigeration machine his best characterized by -
ANSWER ✓ High volume low pressure machine
22.Modern compresses usually sealed the rotating shaft as it exit the
compressor housing a Spring loaded seal made of - ANSWER ✓ Metal or
carbon
23.The British thermal unit BTU is a measurement of heat of energy if 10 be to
you a transfer to 10 pounds of water the water temperature increase will be
closest to - ANSWER ✓ 1ﾟF
24.The Flash point of compressor lubricating oil - ANSWER ✓ Should be
higher than the compression temperature
25.The most common reason for refrigeration engineer to use a psychrommeter
is to measure - ANSWER ✓ Relatively humidity level of the atmosphere
26.Under normal conditions the refrigerant enters the Compressor as a -
ANSWER ✓ Low pressure superheated vapor and leaves as a high pressure
of vapor
27.What is the function of the vacuum breaker in a steam turbine - ANSWER ✓
To achieve a faster coast down cycle
28.An equalizer line on TXV is used for - ANSWER ✓ Compensate for the
pressure drop across the evaporator coil
, 29.In a multistage and a typical compressor each stage Is - ANSWER ✓
Identicle in volume to the other stages
30.In relation to the suction pressure of a compressor the reading of the oil
pressure gauge should read in a range closer to - ANSWER ✓ 15 to 30 PSI
above the suction pressure
31.A condenser pump is supplied with 85 degree water from a cooling tower
and returns to the tower at 88 degrees Engineer is sure the condenser tubes
are clean and free of obstructions. The condenser has high condenser
pressure. The reason for this could be? - ANSWER ✓ Overcharge of
refrigerant
32.What is the lowest temperature a cooling tower can be? - ANSWER ✓ Wet
bulb temperature
33.Manifold hoses should be equipped with? - ANSWER ✓ Low loss fittings
34.Water regulating valves are used to? - ANSWER ✓ Maintain condenser
pressure to a pre-determined level
35.You are the only engineer on duty with a machine running. A vice president
tells you to shovel snow. What should you do? - ANSWER ✓ Do not leave
building
36.How often must you do emergency power testing? - ANSWER ✓ Monthly
37.What is the responsibility of a B29 COF holder? - ANSWER ✓ Inspect the
battery system
38.Why is a refrigerant gauge called a compound gauge? - ANSWER ✓ It reads
positive pressure and vacuum
39.Which of the following does not require flame resistant treatment? -
ANSWER ✓ Art work in a museum
