FDNY Z-51 Refrigeration Exam | Comprehensive Questions & Verified Answers
Efficiency of the refrigerant cycle is affected by the Lowering the condensing pressure
operations of the condenser. Of the following, a more
efficient centrifugal compressor operation results from:
The heat removed from the refrigerant in a condenser is: Sensible and latent heat
The refrigerant unit that you have been assigned to is Are approved by the US Dept. of Transportation
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:
Which of the following best describes how the cylinder Keep in the suction valve opened while the compressor is in the return stroke
unloader works?
In most semi-hermetic compressors, the suction vapor is Cool the motor
used to:
The amount of refrigerant that flows through the orifices Differences between the high side and low side pressure
of an economizer is determined by the:
The installation of an inline refrigerant cleaning system is To remove impurities from the system
advisable:
The type of refrigerant system that is least likely to leak Indirect system
refrigerant into the building space that are being cooled:
The suction pressure of a reciprocating compressor is 65 1.69
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 verifies that a condenser water A faulty cooling tower water level controller
pump is cavitating. Of the following, the most likely cause
for this condition is:
A centrifugal water pump is known as a lift pump when The water supply to the pump suction inlet is below the pump level
the:
A TXV is used to maintain constant: Evaporator superheat
The chilled water supply to the building is 55 deg F. If the Yes, this temp is too high for human comfort purposes
chiller is being used for human comfort, should you be
concerned about this, and why?
The packing gland of a centrifugal pump serves to: The drip part of the packing gland gives evidence that there is water in the pump
, FDNY Z-51 Refrigeration Exam | Comprehensive Questions & Verified Answers
Capacity control of reciprocating hermetic compressor is Operation of the hot gas bypass valve
typically achieved through:
The most important reason to sub-cool the refrigerant in A pure liquid refrigerant will enter the metering device
the condenser is to ensure that:
A refrigeration engineer is logging readings from a An expansion valve that is open too wide
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?
A low side float valve is used to maintain: The level of the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety A1
classification indicates no flammability and lower
toxicity?
When an expansion valve is operating properly, at the Only superheated vapor
end of the evaporator will contain:
What information is not contained in a Material Safety Cost of the material
Data Sheet?
In a steam turbine, what is the function of the Kingsbury Maintain axial positioning of the rotor shaft
thrust bearing?
A centrifugal water pump is considered to the fully The pump is full of liquid
primed when?
Copper tubing refrigerant lines must be installed for a Level type tubing bender
new system. It is a well known service practice that
tubing collapses at bends that must be made, the
refrigerant engineer should use?
A reciprocating compressor is making a knocking sound Slugging of the liquid refrigerant
during operation. If the refrigerant worn parts are not
causing the knocking, what probably the cause?
In order for a refrigerant to become superheated, it must Where no liquid refrigerant is present
be heated in a section of the low side refrigerant line:
All liquid has been recovered from a system to be Should not be opened until all vapor has been recovered
overhauled, the system:
When a refrigerant engineer uses a portable compressor The compressor efficiency is decreasing
recovery unit to remove vapor refrigerant from a
refrigeration system the removal rate of the refrigerant
will gradually slow down because?
, FDNY Z-51 Refrigeration Exam | Comprehensive Questions & Verified Answers
You are the engineer running a 2000-ton (steam driven Add additional make up water to the cooling tower
turbine) centrifugal refrigeration system, a refrigeration
system supplies chilled water to a college campus with
multiple buildings. During the course of making your
rounds, you check the 9 cell cooling tower on the roof.
You note the water level in all of the cooling tower cells is
very low. Which one of the following immediate actions
would take?
A rooftop water cooling tower is connected to a water 323
pump in the building basement with a 12 inch diameter
pipe. With the pipe turned off, a pressure gauge at the
pumps inlet show a pressure of 140 PSIG the height of
the water column, in feet, would be closest to:
What device protects the steam turbine from excessive Governor assembly
speed?
A refrigeration compressor has failed to turn on. The Temperature and pressure controls
refrigeration engineer on duty verifies that the electrical
circuit to the motor, including all switches and circuit
breakers, is complete according to recommended
service practice, the next item to be checked would likely
be the:
Refrigerants are characterized by their physical Ammonia
properties included flashpoint, refrigeration effect, and
others. Of the refrigerants in commercial and industrial,
the one with the highest latent heat and refrigerant effect
is:
Of what characteristics is ASHRAE refrigerant safety Flammability and toxicity
group classification system:
Of the following, an example of an in line refrigerant Recycling
cleaning system that may be used with a centrifugal
compressor containing R-123 refrigerant is:
Information about the physical and chemical properties Material Safety Data Sheet
of a hazardous material can be found in:
What is the function of the turbine auxiliary oil pump? Establish oil pressure during turbine start up
The rupture disc for a low pressure centrifugal Compressor suction
refrigeration machine is normally located on the:
What is the primary reason ribbed metal piping is used It allows for flexibility and accounts for vibrations
for electrical wires connected to the refrigeration system
shown below?
A multi cylinder reciprocating compressor uses cylinder The chill water temperature will increase
unloaders to regulate capacity, what would not occur if
some of the unloaders fail to operate when needed?
As shown in the picture below, the suction gauge of a 440
condenser water pump reads 55 PSI. The pipe supplying
the pump is 75 feet long and 12 inches in diameter.
Approximately, how many gallons of water do you expect
to obtain if the pipe is drained completely?
Efficiency of the refrigerant cycle is affected by the Lowering the condensing pressure
operations of the condenser. Of the following, a more
efficient centrifugal compressor operation results from:
The heat removed from the refrigerant in a condenser is: Sensible and latent heat
The refrigerant unit that you have been assigned to is Are approved by the US Dept. of Transportation
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:
Which of the following best describes how the cylinder Keep in the suction valve opened while the compressor is in the return stroke
unloader works?
In most semi-hermetic compressors, the suction vapor is Cool the motor
used to:
The amount of refrigerant that flows through the orifices Differences between the high side and low side pressure
of an economizer is determined by the:
The installation of an inline refrigerant cleaning system is To remove impurities from the system
advisable:
The type of refrigerant system that is least likely to leak Indirect system
refrigerant into the building space that are being cooled:
The suction pressure of a reciprocating compressor is 65 1.69
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 verifies that a condenser water A faulty cooling tower water level controller
pump is cavitating. Of the following, the most likely cause
for this condition is:
A centrifugal water pump is known as a lift pump when The water supply to the pump suction inlet is below the pump level
the:
A TXV is used to maintain constant: Evaporator superheat
The chilled water supply to the building is 55 deg F. If the Yes, this temp is too high for human comfort purposes
chiller is being used for human comfort, should you be
concerned about this, and why?
The packing gland of a centrifugal pump serves to: The drip part of the packing gland gives evidence that there is water in the pump
, FDNY Z-51 Refrigeration Exam | Comprehensive Questions & Verified Answers
Capacity control of reciprocating hermetic compressor is Operation of the hot gas bypass valve
typically achieved through:
The most important reason to sub-cool the refrigerant in A pure liquid refrigerant will enter the metering device
the condenser is to ensure that:
A refrigeration engineer is logging readings from a An expansion valve that is open too wide
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?
A low side float valve is used to maintain: The level of the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety A1
classification indicates no flammability and lower
toxicity?
When an expansion valve is operating properly, at the Only superheated vapor
end of the evaporator will contain:
What information is not contained in a Material Safety Cost of the material
Data Sheet?
In a steam turbine, what is the function of the Kingsbury Maintain axial positioning of the rotor shaft
thrust bearing?
A centrifugal water pump is considered to the fully The pump is full of liquid
primed when?
Copper tubing refrigerant lines must be installed for a Level type tubing bender
new system. It is a well known service practice that
tubing collapses at bends that must be made, the
refrigerant engineer should use?
A reciprocating compressor is making a knocking sound Slugging of the liquid refrigerant
during operation. If the refrigerant worn parts are not
causing the knocking, what probably the cause?
In order for a refrigerant to become superheated, it must Where no liquid refrigerant is present
be heated in a section of the low side refrigerant line:
All liquid has been recovered from a system to be Should not be opened until all vapor has been recovered
overhauled, the system:
When a refrigerant engineer uses a portable compressor The compressor efficiency is decreasing
recovery unit to remove vapor refrigerant from a
refrigeration system the removal rate of the refrigerant
will gradually slow down because?
, FDNY Z-51 Refrigeration Exam | Comprehensive Questions & Verified Answers
You are the engineer running a 2000-ton (steam driven Add additional make up water to the cooling tower
turbine) centrifugal refrigeration system, a refrigeration
system supplies chilled water to a college campus with
multiple buildings. During the course of making your
rounds, you check the 9 cell cooling tower on the roof.
You note the water level in all of the cooling tower cells is
very low. Which one of the following immediate actions
would take?
A rooftop water cooling tower is connected to a water 323
pump in the building basement with a 12 inch diameter
pipe. With the pipe turned off, a pressure gauge at the
pumps inlet show a pressure of 140 PSIG the height of
the water column, in feet, would be closest to:
What device protects the steam turbine from excessive Governor assembly
speed?
A refrigeration compressor has failed to turn on. The Temperature and pressure controls
refrigeration engineer on duty verifies that the electrical
circuit to the motor, including all switches and circuit
breakers, is complete according to recommended
service practice, the next item to be checked would likely
be the:
Refrigerants are characterized by their physical Ammonia
properties included flashpoint, refrigeration effect, and
others. Of the refrigerants in commercial and industrial,
the one with the highest latent heat and refrigerant effect
is:
Of what characteristics is ASHRAE refrigerant safety Flammability and toxicity
group classification system:
Of the following, an example of an in line refrigerant Recycling
cleaning system that may be used with a centrifugal
compressor containing R-123 refrigerant is:
Information about the physical and chemical properties Material Safety Data Sheet
of a hazardous material can be found in:
What is the function of the turbine auxiliary oil pump? Establish oil pressure during turbine start up
The rupture disc for a low pressure centrifugal Compressor suction
refrigeration machine is normally located on the:
What is the primary reason ribbed metal piping is used It allows for flexibility and accounts for vibrations
for electrical wires connected to the refrigeration system
shown below?
A multi cylinder reciprocating compressor uses cylinder The chill water temperature will increase
unloaders to regulate capacity, what would not occur if
some of the unloaders fail to operate when needed?
As shown in the picture below, the suction gauge of a 440
condenser water pump reads 55 PSI. The pipe supplying
the pump is 75 feet long and 12 inches in diameter.
Approximately, how many gallons of water do you expect
to obtain if the pipe is drained completely?
