FDNY Written z51 Exam Questions With Correct Answers
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Course
FDNY
Institution
FDNY
FDNY Written z51 Exam Questions With
Correct Answers
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: - answerLowering
the condensing pressure
The heat removed from the refri...
FDNY Written z51 Exam Questions With
Correct Answers
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: - answer✔✔Lowering
the condensing pressure
The heat removed from the refrigerant in a condenser is: - 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: - answer✔✔Are
approved by the US department of transportation
Which of the following best describes how the cylinder unloader work? - 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: - answer✔✔Cool the motor
The amount of refrigerant that flows through the orifices of a economizer is determined by the: -
answer✔✔Difference between the high side and load side pressure
The installation of an inline refrigerant cleaning system is advisable: - 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 - 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: - answer✔✔1.69
A super heated vapor is a ? - 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: - answer✔✔A faulty cooling tower water level controller
, THEBRIGHT EXAM SOLUTIONS 8/20/2024 8:37 PM
A centrifugal water pump is known as a lift pump when the: - answer✔✔The water supply to the
pump suction inlet is below the pump level
A TXV is used to maintain constant: - 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? - answer✔✔Yes, this temperature is too high for
human comfort purpose
The packing gland of a centrifugal pump serves to: - 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 -
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
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. - answer✔✔An expansion valve that is open
to wide
A low side float valve is used to maintain: - answer✔✔The level of the refrigerant in the
evaporator
Regarding fire safety, which ASHARE refrigerant safety classification indicates no flammability
and lower the toxicity? - answer✔✔A1
When an expansion valve is operating properly, at the end of the evaporator will contain: -
answer✔✔Only superheated vapor
What information is not contained in a material safety data sheet-MSDS? - answer✔✔Cost of
material
In a steam turbine, what is the function of the kingsbury thrust bearing - answer✔✔Maintain
axial positioning of the rotor shaft
A centrifugal water pump is considered to be fully primed when - answer✔✔The pump is full of
liquid
Copper tubing 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 -
answer✔✔Lever type tubing bender
, THEBRIGHT EXAM SOLUTIONS 8/20/2024 8:37 PM
A reciprocating compressor is making a knocking sound during operation. if the refrigerant worn
parts are not causing the knocking, what is probably the cause - answer✔✔The slugging of the
liquid refrigerant
In order for a refrigerant to become superheated in a section of the lowside refrigerant line: -
answer✔✔Where no liquid refrigerant is present
All liquid has been recovered from a system to be overhauled, the system - answer✔✔Should not
be opened until all vapor has been removed
When a refrigerant engineer uses a portable compressor recovery unit to remove vapor
refrigerant from a refrigeration system the removal rate of the refrigerant will gradually slow
down because - answer✔✔The vapor density is decreasing
You are the engineer running a 2000-ton (steam-driven 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
action would take? - answer✔✔Add additional make up water to cooling tower
A rooftop water cooling tower is connected to a water pump in the building basement with a 12
inches diameter pipe. with the pump turn off, a pressure gauge at the pumps inlet show a
pressure of 140 PSIG the height of the water column, in feet, would be closet to. - answer✔✔323
What device protects the steam turbine from excessive speed? - answer✔✔governor assembly
A refrigeration compressor has failed to turn on. the 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: -
answer✔✔Temperature and pressure controls
Refrigerants are characterized by their physical properties included flash point, refrigeration
effect, and others. of the refrigerant in commercial and industrial the highest latent hear and
refrigerant effect is: - answer✔✔Ammonia
On what characteristics is ASHRAE refrigerant safety group classification system: -
answer✔✔Flammability and toxicity
Of the following, and example of an in-line refrigerant cleaning system that may be used with 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:
- answer✔✔Material Safety Data Sheet
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