Z-51 EXAM 7 QUESTIONS WITH 100%
CORRECT ANSWERS!!
What is a superheated vapor?
completely dry vapor
In electrical circuits the conductor is always what color?
Green or Bare
Unloaders are used for what?
To increase capacity
Oil foaming in a crankcase is caused by what?
A sudden drop in crankcase pressure
How would you test for acid in the refrigerant?
Spraying liquid refrigerant from a condenser or receiver on to bond paper
What is the function of a cylinder bypass?
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?
Yes. this temperature is too high for human comfort purpose
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
Capacity control of a reciprocating hermetic compressor is typically achieved through
Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that:
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.
An expansion valve that is open to wide
A low side float valve is used to maintain:
The level of the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification indicates no
flammability and lower toxicity?
A1
All liquid has been recovered from a system to be overhauled, the system
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
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?
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.
323
What device protects the steam turbine from excessive speed?
, 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:
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:
Ammonia
On what characteristics is ASHRAE refrigerant safety group classification system:
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:
Refrigerant recycling
Information about the physical and chemical properties of a hazardous material can be
found in:
Material Safety Data Sheet
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 refrigeration machine is normally located
on the:
Compressor suction
What is the primary reason ribbed metal piping is used for electrical wires connected to the
refrigeration system shown below?
CORRECT ANSWERS!!
What is a superheated vapor?
completely dry vapor
In electrical circuits the conductor is always what color?
Green or Bare
Unloaders are used for what?
To increase capacity
Oil foaming in a crankcase is caused by what?
A sudden drop in crankcase pressure
How would you test for acid in the refrigerant?
Spraying liquid refrigerant from a condenser or receiver on to bond paper
What is the function of a cylinder bypass?
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?
Yes. this temperature is too high for human comfort purpose
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
Capacity control of a reciprocating hermetic compressor is typically achieved through
Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to ensure that:
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.
An expansion valve that is open to wide
A low side float valve is used to maintain:
The level of the refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification indicates no
flammability and lower toxicity?
A1
All liquid has been recovered from a system to be overhauled, the system
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
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?
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.
323
What device protects the steam turbine from excessive speed?
, 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:
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:
Ammonia
On what characteristics is ASHRAE refrigerant safety group classification system:
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:
Refrigerant recycling
Information about the physical and chemical properties of a hazardous material can be
found in:
Material Safety Data Sheet
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 refrigeration machine is normally located
on the:
Compressor suction
What is the primary reason ribbed metal piping is used for electrical wires connected to the
refrigeration system shown below?
