FDNY Z51_ Z-51
REFRIGERATION EXAM
2025/2026
Exam Prep Material
with
Verified Questions and Answers
A+ Grades Guarantee
, Lowering the condensing pressure
Efficiency of the 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 the Sensible and latent heat
refrigerant in a condenser is:
Are approved by the US Dept. of Transportation
The refrigerant unit that 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:
Keep in the suction valve opened while the compressor is in the
Which of the following best return stroke
describes how the cylinder
unloader works?
Cool the motor
In most semi-hermetic
compressors, the suction vapor is
used to:
Differences between the high side and low side pressure
The amount of refrigerant that
flows through the orifices of an
economizer is determined by the:
To remove impurities from the system
The installation of an inline
refrigerant cleaning system is
advisable:
Indirect system
The type of refrigerant system
that is least likely to leak
refrigerant into the building space
that are being cooled:
1.69
The suction pressure of a
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 faulty cooling tower water level controller
A refrigerant engineer verifies
that a condenser water pump is
cavitating. Of the following, the
most likely cause for this
condition is:
The water supply to the pump suction inlet is below the pump level
A centrifugal water pump is
known as a lift pump when the:
Evaporator superheat
A TXV is used to maintain
constant:
Yes, this temp is too high for human comfort purposes
The chilled water supply to the
building is 55 deg F. If the chiller
is being used for human comfort,
should you be concerned about
this, and why?
The drip part of the packing gland gives evidence that there is
The packing gland of a
water in the pump
centrifugal pump serves to:
Operation of the hot gas bypass valve
Capacity control of reciprocating
hermetic compressor is typically
achieved through:
A pure liquid refrigerant will enter the metering device
The most important reason to
sub-cool the refrigerant in the
condenser is to ensure that:
An expansion valve that is open too wide
A refrigeration engineer 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?
The level of the refrigerant in the evaporator
A low side float valve is used to
maintain:
A1
Regarding fire safety, which
ASHRAE refrigerant safety
classification indicates no
flammability and lower toxicity?
Only superheated vapor
When an expansion valve is
operating properly, at the end of
the evaporator will contain:
REFRIGERATION EXAM
2025/2026
Exam Prep Material
with
Verified Questions and Answers
A+ Grades Guarantee
, Lowering the condensing pressure
Efficiency of the 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 the Sensible and latent heat
refrigerant in a condenser is:
Are approved by the US Dept. of Transportation
The refrigerant unit that 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:
Keep in the suction valve opened while the compressor is in the
Which of the following best return stroke
describes how the cylinder
unloader works?
Cool the motor
In most semi-hermetic
compressors, the suction vapor is
used to:
Differences between the high side and low side pressure
The amount of refrigerant that
flows through the orifices of an
economizer is determined by the:
To remove impurities from the system
The installation of an inline
refrigerant cleaning system is
advisable:
Indirect system
The type of refrigerant system
that is least likely to leak
refrigerant into the building space
that are being cooled:
1.69
The suction pressure of a
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 faulty cooling tower water level controller
A refrigerant engineer verifies
that a condenser water pump is
cavitating. Of the following, the
most likely cause for this
condition is:
The water supply to the pump suction inlet is below the pump level
A centrifugal water pump is
known as a lift pump when the:
Evaporator superheat
A TXV is used to maintain
constant:
Yes, this temp is too high for human comfort purposes
The chilled water supply to the
building is 55 deg F. If the chiller
is being used for human comfort,
should you be concerned about
this, and why?
The drip part of the packing gland gives evidence that there is
The packing gland of a
water in the pump
centrifugal pump serves to:
Operation of the hot gas bypass valve
Capacity control of reciprocating
hermetic compressor is typically
achieved through:
A pure liquid refrigerant will enter the metering device
The most important reason to
sub-cool the refrigerant in the
condenser is to ensure that:
An expansion valve that is open too wide
A refrigeration engineer 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?
The level of the refrigerant in the evaporator
A low side float valve is used to
maintain:
A1
Regarding fire safety, which
ASHRAE refrigerant safety
classification indicates no
flammability and lower toxicity?
Only superheated vapor
When an expansion valve is
operating properly, at the end of
the evaporator will contain:
