FDNY Z51 WRITTEN EXAM ACTUAL
EXAM 2 VERSIONS (VERSION A AND
B) COMPLETE 400 QUESTIONS WITH
DETAILED VERIFIED ANSWERS /
ALREADY GRADED A+
The efficiency of the refrigerant cycle is affected by the operation of the condenser. of the
following. a more efficient centrifugal compressor operation results from: - CORRECT ANSWER-
Lowering the condensing pressure
The heat removed from the refrigerant in a condenser is: - CORRECT ANSWER-Sensible and
latent heat
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 new York city fire code, you must ensure that the containers: - CORRECT
ANSWER-Are approved by the US department of transportation
Which of the following best describes how the cylinder unloader work? - CORRECT ANSWER-
Keep in the suction valve opened while the compressor is in the return stroke
In most semi hermetic compressors, the suction vapor is used to: - CORRECT ANSWER-Cool the
motor
The amount of refrigerant that flows through the orifices of a economizer is determined by the:
- CORRECT ANSWER-Difference between the high side and load side pressure
,The installation of an inline refrigerant cleaning system is advisable: - CORRECT ANSWER-To
remove impurities from the system
The type of refrigerant system that is least likely to leak refrigerant into the building space that
are cooled - CORRECT ANSWER-The indirect system
The suction pressure of a reciprocating compressor is 65PSIG. the discharge pressure of this
compressor is 120PSIG. the atmospheric is 14.7 PSI. the compression ratio for the given
condition is closet to: - CORRECT ANSWER-1.69
A super heated vapor is a ? - CORRECT ANSWER-Dry vapor above the saturation temperature
A refrigerant engineer verifies that a condenser water pump is cavitating. of the following the
most likely cause for this condition is: - CORRECT ANSWER-A faulty cooling tower water level
controller
A centrifugal water pump is known as a lift pump when the: - CORRECT ANSWER-The water
supply to the pump suction inlet is below the pump level
A TXV is used to maintain constant: - CORRECT ANSWER-Evaporator superheat
The chilled water supply to the building is 55F. if the chiller is being used for human comfort,
should you be concerned about this , and why? - CORRECT ANSWER-Yes, this temperature is too
high for human comfort purpose
The packing gland of a centrifugal pump serves to: - CORRECT ANSWER-The drip part of the
packing gland gives evidence that there is water in the pump
, Capacity control of a reciprocating hermetic compressor is typically achieved through - CORRECT
ANSWER-Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that: -
CORRECT ANSWER-A pure liquid refrigerant will enter the metering device
A refrigeration engineer is logging reading 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. - CORRECT ANSWER-An expansion valve that
is open to wide
A low side float valve is used to maintain: - CORRECT ANSWER-The level of the refrigerant in the
evaporator
Regarding fire safety, which ASHARE refrigerant safety classification indicates no flammability
and lower the toxicity? - CORRECT ANSWER-A1
When an expansion valve is operating properly, at the end of the evaporator will contain: -
CORRECT ANSWER-Only superheated vapor
What information is not contained in a material safety data sheet-MSDS? - CORRECT ANSWER-
Cost of material
In a steam turbine, what is the function of the kingsbury thrust bearing - CORRECT ANSWER-
Maintain axial positioning of the rotor shaft
A centrifugal water pump is considered to be fully primed when - CORRECT ANSWER-The pump
is full of liquid
EXAM 2 VERSIONS (VERSION A AND
B) COMPLETE 400 QUESTIONS WITH
DETAILED VERIFIED ANSWERS /
ALREADY GRADED A+
The efficiency of the refrigerant cycle is affected by the operation of the condenser. of the
following. a more efficient centrifugal compressor operation results from: - CORRECT ANSWER-
Lowering the condensing pressure
The heat removed from the refrigerant in a condenser is: - CORRECT ANSWER-Sensible and
latent heat
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 new York city fire code, you must ensure that the containers: - CORRECT
ANSWER-Are approved by the US department of transportation
Which of the following best describes how the cylinder unloader work? - CORRECT ANSWER-
Keep in the suction valve opened while the compressor is in the return stroke
In most semi hermetic compressors, the suction vapor is used to: - CORRECT ANSWER-Cool the
motor
The amount of refrigerant that flows through the orifices of a economizer is determined by the:
- CORRECT ANSWER-Difference between the high side and load side pressure
,The installation of an inline refrigerant cleaning system is advisable: - CORRECT ANSWER-To
remove impurities from the system
The type of refrigerant system that is least likely to leak refrigerant into the building space that
are cooled - CORRECT ANSWER-The indirect system
The suction pressure of a reciprocating compressor is 65PSIG. the discharge pressure of this
compressor is 120PSIG. the atmospheric is 14.7 PSI. the compression ratio for the given
condition is closet to: - CORRECT ANSWER-1.69
A super heated vapor is a ? - CORRECT ANSWER-Dry vapor above the saturation temperature
A refrigerant engineer verifies that a condenser water pump is cavitating. of the following the
most likely cause for this condition is: - CORRECT ANSWER-A faulty cooling tower water level
controller
A centrifugal water pump is known as a lift pump when the: - CORRECT ANSWER-The water
supply to the pump suction inlet is below the pump level
A TXV is used to maintain constant: - CORRECT ANSWER-Evaporator superheat
The chilled water supply to the building is 55F. if the chiller is being used for human comfort,
should you be concerned about this , and why? - CORRECT ANSWER-Yes, this temperature is too
high for human comfort purpose
The packing gland of a centrifugal pump serves to: - CORRECT ANSWER-The drip part of the
packing gland gives evidence that there is water in the pump
, Capacity control of a reciprocating hermetic compressor is typically achieved through - CORRECT
ANSWER-Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that: -
CORRECT ANSWER-A pure liquid refrigerant will enter the metering device
A refrigeration engineer is logging reading 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. - CORRECT ANSWER-An expansion valve that
is open to wide
A low side float valve is used to maintain: - CORRECT ANSWER-The level of the refrigerant in the
evaporator
Regarding fire safety, which ASHARE refrigerant safety classification indicates no flammability
and lower the toxicity? - CORRECT ANSWER-A1
When an expansion valve is operating properly, at the end of the evaporator will contain: -
CORRECT ANSWER-Only superheated vapor
What information is not contained in a material safety data sheet-MSDS? - CORRECT ANSWER-
Cost of material
In a steam turbine, what is the function of the kingsbury thrust bearing - CORRECT ANSWER-
Maintain axial positioning of the rotor shaft
A centrifugal water pump is considered to be fully primed when - CORRECT ANSWER-The pump
is full of liquid
