FDNY A-35 EXAM LATEST ACTUAL EXAM 100
QUESTIONS AND CORRECT DETAILED ANSWERS
(100%VERIFIED ANSWERS) |AGRADE
A more efficient centrifugal compressor operation results from - ANSWER: Lowering
the condensing pressure
The heat removed from the refrigerant in a condenser is - ANSWER: Sensible and
latent heat
According to the New York City fire code, refrigerant containers must - ANSWER: Be
approved by the US Department of Transportation
The cylinder unloader works by - ANSWER: Keeping the suction valve opened while
the compressor is in the return stroke
In most semi-hermetic compressors, the suction vapor is used to - ANSWER: Cool the
motor
The amount of refrigerant that flows through the orifices of an economizer is
determined by the - ANSWER: Difference between the high side and low side
pressure
The installation of an inline refrigerant cleaning system is advisable to - ANSWER:
Remove impurities from the system
The type of refrigerant system least likely to leak refrigerant into the building space
is - ANSWER: The indirect system
The compression ratio for a reciprocating compressor with a suction pressure of 65
PSIG and a discharge pressure of 120 PSIG is closest to - ANSWER: 1.69
A superheated vapor is - ANSWER: Dry vapor above the saturation temperature
A condenser water pump cavitating is most likely caused by - ANSWER: A faulty
cooling tower water level controller
A centrifugal water pump is known as a lift pump when - ANSWER: The water supply
to the pump suction inlet is below the pump level
A TXV is used to maintain constant - ANSWER: Evaporator superheat
A chilled water supply of 55°F for human comfort is - ANSWER: Too high for human
comfort purpose
,The packing gland of a centrifugal pump serves to - ANSWER: Keep air out of the
pumps when the impeller housing is under negative pressure
Capacity control of a reciprocating hermetic compressor is typically achieved through
- ANSWER: Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure
that - ANSWER: A pure liquid refrigerant will enter the metering device
If a compressor discharge temperature has dropped significantly and the suction line
pressure is high, this may be caused by - ANSWER: An expansion valve that is open
too wide
A low side float valve is used to maintain - ANSWER: The level of the refrigerant in
the evaporator
The ASHRAE refrigerant safety classification indicating no flammability and lower
toxicity is - ANSWER: A1
When an expansion valve is operating properly, the end of the evaporator will
contain - ANSWER: Only superheated vapor
Information not contained in a Material Safety Data Sheet (MSDS) includes -
ANSWER: Cost of the material
In a steam turbine, the Kingsbury thrust bearing functions to - ANSWER: Maintain
axial positioning of the rotor shaft
A centrifugal water pump is considered fully primed when - ANSWER: The pump is
full of liquid
To avoid collapsing tubing when making bends, a refrigerant engineer should use -
ANSWER: Lever type tubing bender
A reciprocating compressor making a clicking sound during operation, if not caused
by worn parts, is probably due to - ANSWER: Slugging of the liquid refrigerant
For a refrigerant to become superheated, it must be heated in a section of the low
side refrigerant line - ANSWER: Where no liquid refrigerant is present
After all liquid refrigerant has been recovered, the system - ANSWER: Should not be
opened until all vapor has been recovered
The removal rate of refrigerant using a portable compressor recovery unit gradually
slows down because - ANSWER: The vapor density is decreasing
, If the water level in all cooling tower cells is very low, the immediate action should
be to - ANSWER: Add additional makeup water to the cooling tower
The height of the water column, in feet, with a pressure gauge reading 140 PSIG is
closest to - ANSWER: 323 feet
The device that protects a steam turbine from excessive speed is the - ANSWER:
Governor assembly
If a refrigeration compressor fails to turn on, after verifying the electrical circuit, the
next item to check would be the - ANSWER: Temperature and pressure controls
Of the refrigerants in commercial and industrial use, the one with the highest latent
heat and refrigerant effect is - ANSWER: Ammonia
The ASHRAE refrigerant safety group classification system is based on - ANSWER:
Flammability and toxicity
An example of an in-line refrigerant cleaning system for a centrifugal compressor
containing R123 refrigerant is - ANSWER: Refrigerant recycling
Information about the physical and chemical properties of a hazardous material can
be found in the - ANSWER: Material Safety Data Sheet (MSDS)
The function of the turbine auxiliary oil pump is to - ANSWER: Establish oil pressure
during turbine start-up
The rupture disc for a low-pressure centrifugal refrigeration machine is normally
located on the - ANSWER: Compressor suction
Ribbed metal piping is used for electrical wires connected to the refrigeration system
primarily because - ANSWER: It allows for flexibility and accounts for vibrations
If some of the cylinder unloaders on a multi-cylinder reciprocating compressor fail to
operate, one likely outcome is that - ANSWER: The chilled water temperature will
increase
If the suction gauge of a condenser water pump reads 55 PSI, draining the 75 feet
long, 12-inch diameter pipe would yield approximately - ANSWER: 440 gallons of
water
A leak in the evaporator shell of a system using R123 refrigerant might result in -
ANSWER: A higher than normal high side pressure
The function of capacitors used on refrigeration motors is to - ANSWER: Store
electrical charges during starting and running the motor
QUESTIONS AND CORRECT DETAILED ANSWERS
(100%VERIFIED ANSWERS) |AGRADE
A more efficient centrifugal compressor operation results from - ANSWER: Lowering
the condensing pressure
The heat removed from the refrigerant in a condenser is - ANSWER: Sensible and
latent heat
According to the New York City fire code, refrigerant containers must - ANSWER: Be
approved by the US Department of Transportation
The cylinder unloader works by - ANSWER: Keeping the suction valve opened while
the compressor is in the return stroke
In most semi-hermetic compressors, the suction vapor is used to - ANSWER: Cool the
motor
The amount of refrigerant that flows through the orifices of an economizer is
determined by the - ANSWER: Difference between the high side and low side
pressure
The installation of an inline refrigerant cleaning system is advisable to - ANSWER:
Remove impurities from the system
The type of refrigerant system least likely to leak refrigerant into the building space
is - ANSWER: The indirect system
The compression ratio for a reciprocating compressor with a suction pressure of 65
PSIG and a discharge pressure of 120 PSIG is closest to - ANSWER: 1.69
A superheated vapor is - ANSWER: Dry vapor above the saturation temperature
A condenser water pump cavitating is most likely caused by - ANSWER: A faulty
cooling tower water level controller
A centrifugal water pump is known as a lift pump when - ANSWER: The water supply
to the pump suction inlet is below the pump level
A TXV is used to maintain constant - ANSWER: Evaporator superheat
A chilled water supply of 55°F for human comfort is - ANSWER: Too high for human
comfort purpose
,The packing gland of a centrifugal pump serves to - ANSWER: Keep air out of the
pumps when the impeller housing is under negative pressure
Capacity control of a reciprocating hermetic compressor is typically achieved through
- ANSWER: Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure
that - ANSWER: A pure liquid refrigerant will enter the metering device
If a compressor discharge temperature has dropped significantly and the suction line
pressure is high, this may be caused by - ANSWER: An expansion valve that is open
too wide
A low side float valve is used to maintain - ANSWER: The level of the refrigerant in
the evaporator
The ASHRAE refrigerant safety classification indicating no flammability and lower
toxicity is - ANSWER: A1
When an expansion valve is operating properly, the end of the evaporator will
contain - ANSWER: Only superheated vapor
Information not contained in a Material Safety Data Sheet (MSDS) includes -
ANSWER: Cost of the material
In a steam turbine, the Kingsbury thrust bearing functions to - ANSWER: Maintain
axial positioning of the rotor shaft
A centrifugal water pump is considered fully primed when - ANSWER: The pump is
full of liquid
To avoid collapsing tubing when making bends, a refrigerant engineer should use -
ANSWER: Lever type tubing bender
A reciprocating compressor making a clicking sound during operation, if not caused
by worn parts, is probably due to - ANSWER: Slugging of the liquid refrigerant
For a refrigerant to become superheated, it must be heated in a section of the low
side refrigerant line - ANSWER: Where no liquid refrigerant is present
After all liquid refrigerant has been recovered, the system - ANSWER: Should not be
opened until all vapor has been recovered
The removal rate of refrigerant using a portable compressor recovery unit gradually
slows down because - ANSWER: The vapor density is decreasing
, If the water level in all cooling tower cells is very low, the immediate action should
be to - ANSWER: Add additional makeup water to the cooling tower
The height of the water column, in feet, with a pressure gauge reading 140 PSIG is
closest to - ANSWER: 323 feet
The device that protects a steam turbine from excessive speed is the - ANSWER:
Governor assembly
If a refrigeration compressor fails to turn on, after verifying the electrical circuit, the
next item to check would be the - ANSWER: Temperature and pressure controls
Of the refrigerants in commercial and industrial use, the one with the highest latent
heat and refrigerant effect is - ANSWER: Ammonia
The ASHRAE refrigerant safety group classification system is based on - ANSWER:
Flammability and toxicity
An example of an in-line refrigerant cleaning system for a centrifugal compressor
containing R123 refrigerant is - ANSWER: Refrigerant recycling
Information about the physical and chemical properties of a hazardous material can
be found in the - ANSWER: Material Safety Data Sheet (MSDS)
The function of the turbine auxiliary oil pump is to - ANSWER: Establish oil pressure
during turbine start-up
The rupture disc for a low-pressure centrifugal refrigeration machine is normally
located on the - ANSWER: Compressor suction
Ribbed metal piping is used for electrical wires connected to the refrigeration system
primarily because - ANSWER: It allows for flexibility and accounts for vibrations
If some of the cylinder unloaders on a multi-cylinder reciprocating compressor fail to
operate, one likely outcome is that - ANSWER: The chilled water temperature will
increase
If the suction gauge of a condenser water pump reads 55 PSI, draining the 75 feet
long, 12-inch diameter pipe would yield approximately - ANSWER: 440 gallons of
water
A leak in the evaporator shell of a system using R123 refrigerant might result in -
ANSWER: A higher than normal high side pressure
The function of capacitors used on refrigeration motors is to - ANSWER: Store
electrical charges during starting and running the motor
