2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
FDNY Z51/ Z-51 REFRIGERATION EXAM (2025)
comprehensive questions and verified answers (
detailed & elaborated) ACTUAL EXAM 2025
TEST!!
Save
Terms in this set (247)
Efficiency of the Lowering the condensing pressure
refrigerant cycle is
affected by the
operations of the
condenser. Of the
following, a more
efficient centrifugal
compressor operation
results from:
The heat removed from Sensible and latent heat
the refrigerant in a
condenser is:
The refrigerant unit that Are approved by the US Dept. of Transportation
you have been assigned
to is being taken out of
service for a major repair.
You have been assigned
to withdraw refrigerant
for storage in suitable
containers. According to
the NYC Fire Code, you
must ensure that the
containers:
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 1/37
,2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
Which of the following Keep in the suction valve opened while the
best describes how the compressor is in the return stroke
cylinder unloader works?
In most semi-hermetic Cool the motor
compressors, the suction
vapor is used to:
The amount of refrigerant Differences between the high side and low side
that flows through the pressure
orifices of an economizer
is determined by the:
The installation of an To remove impurities from the system
inline refrigerant cleaning
system is advisable:
The type of refrigerant Indirect system
system that is least likely
to leak refrigerant into
the building space that
are being cooled:
The suction pressure of a 1.69
reciprocating
compressor is 65 PSIG.
The discharge pressure
of this compressor is 120
PSIG. The atmospheric is
14.7 PSI. The compression
ratio for the given
condition is closest to:
A superheated vapor is: Dry vapor above the saturation temperature
A refrigerant engineer A faulty cooling tower water level controller
verifies that a condenser
water pump is cavitating.
Of the following, the
most likely cause for this
condition is:
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,2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
A centrifugal water pump The water supply to the pump suction inlet is below
is known as a lift pump the pump level
when the:
A TXV is used to maintain Evaporator superheat
constant:
The chilled water supply Yes, this temp is too high for human comfort
to the building is 55 deg purposes
F. If the chiller is being
used for human comfort,
should you be
concerned about this,
and why?
The packing gland of a The drip part of the packing gland gives evidence
centrifugal pump serves that there is water in the pump
to:
Capacity control of Operation of the hot gas bypass valve
reciprocating hermetic
compressor is typically
achieved through:
The most important A pure liquid refrigerant will enter the metering
reason to sub-cool the device
refrigerant in the
condenser is to ensure
that:
A refrigeration engineer An expansion valve that is open too wide
is logging readings from
a reciprocating system.
Compressor discharge
temperature have
dropped significantly and
the suction line pressure
is high. Which of the
following that may be
causing this set of
condition?
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 3/37
, 2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
A low side float valve is The level of the refrigerant in the evaporator
used to maintain:
Regarding fire safety, A1
which ASHRAE
refrigerant safety
classification indicates no
flammability and lower
toxicity?
When an expansion valve Only superheated vapor
is operating properly, at
the end of the
evaporator will contain:
What information is not Cost of the material
contained in a Material
Safety Data Sheet?
In a steam turbine, what Maintain axial positioning of the rotor shaft
is the function of the
Kingsbury thrust bearing?
A centrifugal water pump The pump is full of liquid
is considered to the fully
primed when?
Copper tubing Level type tubing bender
refrigerant lines must be
installed for a new
system. It is a well known
service practice that
tubing collapses at bends
that must be made, the
refrigerant engineer
should use?
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 4/37
FDNY Z51/ Z-51 REFRIGERATION EXAM (2025)
comprehensive questions and verified answers (
detailed & elaborated) ACTUAL EXAM 2025
TEST!!
Save
Terms in this set (247)
Efficiency of the Lowering the condensing pressure
refrigerant cycle is
affected by the
operations of the
condenser. Of the
following, a more
efficient centrifugal
compressor operation
results from:
The heat removed from Sensible and latent heat
the refrigerant in a
condenser is:
The refrigerant unit that Are approved by the US Dept. of Transportation
you have been assigned
to is being taken out of
service for a major repair.
You have been assigned
to withdraw refrigerant
for storage in suitable
containers. According to
the NYC Fire Code, you
must ensure that the
containers:
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 1/37
,2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
Which of the following Keep in the suction valve opened while the
best describes how the compressor is in the return stroke
cylinder unloader works?
In most semi-hermetic Cool the motor
compressors, the suction
vapor is used to:
The amount of refrigerant Differences between the high side and low side
that flows through the pressure
orifices of an economizer
is determined by the:
The installation of an To remove impurities from the system
inline refrigerant cleaning
system is advisable:
The type of refrigerant Indirect system
system that is least likely
to leak refrigerant into
the building space that
are being cooled:
The suction pressure of a 1.69
reciprocating
compressor is 65 PSIG.
The discharge pressure
of this compressor is 120
PSIG. The atmospheric is
14.7 PSI. The compression
ratio for the given
condition is closest to:
A superheated vapor is: Dry vapor above the saturation temperature
A refrigerant engineer A faulty cooling tower water level controller
verifies that a condenser
water pump is cavitating.
Of the following, the
most likely cause for this
condition is:
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 2/37
,2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
A centrifugal water pump The water supply to the pump suction inlet is below
is known as a lift pump the pump level
when the:
A TXV is used to maintain Evaporator superheat
constant:
The chilled water supply Yes, this temp is too high for human comfort
to the building is 55 deg purposes
F. If the chiller is being
used for human comfort,
should you be
concerned about this,
and why?
The packing gland of a The drip part of the packing gland gives evidence
centrifugal pump serves that there is water in the pump
to:
Capacity control of Operation of the hot gas bypass valve
reciprocating hermetic
compressor is typically
achieved through:
The most important A pure liquid refrigerant will enter the metering
reason to sub-cool the device
refrigerant in the
condenser is to ensure
that:
A refrigeration engineer An expansion valve that is open too wide
is logging readings from
a reciprocating system.
Compressor discharge
temperature have
dropped significantly and
the suction line pressure
is high. Which of the
following that may be
causing this set of
condition?
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 3/37
, 2/17/25, 8:45 AM FDNY Z51/ Z-51 REFRIGERATION EXAM (2025) comprehensive questions and verified answers ( detailed & elaborated) ACT…
A low side float valve is The level of the refrigerant in the evaporator
used to maintain:
Regarding fire safety, A1
which ASHRAE
refrigerant safety
classification indicates no
flammability and lower
toxicity?
When an expansion valve Only superheated vapor
is operating properly, at
the end of the
evaporator will contain:
What information is not Cost of the material
contained in a Material
Safety Data Sheet?
In a steam turbine, what Maintain axial positioning of the rotor shaft
is the function of the
Kingsbury thrust bearing?
A centrifugal water pump The pump is full of liquid
is considered to the fully
primed when?
Copper tubing Level type tubing bender
refrigerant lines must be
installed for a new
system. It is a well known
service practice that
tubing collapses at bends
that must be made, the
refrigerant engineer
should use?
https://quizlet.com/1006787545/fdny-z51-z-51-refrigeration-exam-2025-comprehensive-questions-and-verified-answers-detailed-elaborated-actu… 4/37
