FDNY Z51 Test - Questions With Correct Solutions
What is a superheated vapor? Right Ans - completely dry vapor
In electrical circuits the conductor is always what color? Right
Ans - Green or Bare
Unloaders are used for what? Right Ans - To increase capacity
Oil foaming in a crankcase is caused by what? Right Ans - A
sudden drop in crankcase pressure
How would you test for acid in the refrigerant? Right Ans -
Spraying liquid refrigerant from a condenser or receiver on to bond
paper
What is the function of a cylinder bypass? Right Ans - To allow
operation at different capacities
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? Right Ans - Yes. this temperature is too high for human
comfort purpose
,The packing gland of a centrifugal pump serves to: Right Ans -
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 Right Ans - Operation of the hot gas bypass
valve
The most important reason to sub-cool the refrigerant in the
condenser is to ensure that: Right Ans - 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. Right Ans - An
expansion valve that is open to wide
A low side float valve is used to maintain: Right Ans - The level of
the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower toxicity? Right Ans - A1
,All liquid has been recovered from a system to be overhauled, the
system Right Ans - Should not be opened until all vapor has been
recovered
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
Right Ans - 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?
Right Ans - 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.
Right Ans - 323
What device protects the steam turbine from excessive speed?
Right Ans - 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: Right Ans - Temperature and pressure controls
Refrigerants are characterized by their physical properties included
flashpoint, refrigeration effect, and others. Of the refrigerants in
commercial and industrial the highest latent heat and refrigerant
effect is: Right Ans - Ammonia
On what characteristics is ASHRAE refrigerant safety group
classification system: Right Ans - 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: Right Ans - Refrigerant recycling
Information about the physical and chemical properties of a
hazardous material can be found in: Right Ans - Material Safety
Data Sheet
What is the function of the turbine auxiliary oil pump? Right Ans
- Establish oil pressure during turbine start up
What is a superheated vapor? Right Ans - completely dry vapor
In electrical circuits the conductor is always what color? Right
Ans - Green or Bare
Unloaders are used for what? Right Ans - To increase capacity
Oil foaming in a crankcase is caused by what? Right Ans - A
sudden drop in crankcase pressure
How would you test for acid in the refrigerant? Right Ans -
Spraying liquid refrigerant from a condenser or receiver on to bond
paper
What is the function of a cylinder bypass? Right Ans - To allow
operation at different capacities
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? Right Ans - Yes. this temperature is too high for human
comfort purpose
,The packing gland of a centrifugal pump serves to: Right Ans -
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 Right Ans - Operation of the hot gas bypass
valve
The most important reason to sub-cool the refrigerant in the
condenser is to ensure that: Right Ans - 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. Right Ans - An
expansion valve that is open to wide
A low side float valve is used to maintain: Right Ans - The level of
the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower toxicity? Right Ans - A1
,All liquid has been recovered from a system to be overhauled, the
system Right Ans - Should not be opened until all vapor has been
recovered
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
Right Ans - 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?
Right Ans - 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.
Right Ans - 323
What device protects the steam turbine from excessive speed?
Right Ans - 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: Right Ans - Temperature and pressure controls
Refrigerants are characterized by their physical properties included
flashpoint, refrigeration effect, and others. Of the refrigerants in
commercial and industrial the highest latent heat and refrigerant
effect is: Right Ans - Ammonia
On what characteristics is ASHRAE refrigerant safety group
classification system: Right Ans - 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: Right Ans - Refrigerant recycling
Information about the physical and chemical properties of a
hazardous material can be found in: Right Ans - Material Safety
Data Sheet
What is the function of the turbine auxiliary oil pump? Right Ans
- Establish oil pressure during turbine start up
