Z-51 REFRIGERATION TEST questions
and answers
Lowering the condensing pressure - correct answer ✔✔ Efficiency of the refrigerant cycle is
affected by the operations of the condenser. Of the following, a more efficient centrifugal
compressor operation results from:
Sensible and latent heat - correct answer ✔✔ The heat removed from the refrigerant in a
condenser is:
Are approved by the US Dept. of Transportation - correct answer ✔✔ 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 NYC Fire
Code, you must ensure that the containers:
Keep in the suction valve opened while the compressor is in the return stroke - correct answer
✔✔ Which of the following best describes how the cylinder unloader works?
Cool the motor - correct answer ✔✔ In most semi-hermetic compressors, the suction vapor is
used to:
Differences between the high side and low side pressure - correct answer ✔✔ The amount of
refrigerant that flows through the orifices of an economizer is determined by the:
To remove impurities from the system - correct answer ✔✔ The installation of an inline
refrigerant cleaning system is advisable:
,Indirect system - correct answer ✔✔ The type of refrigerant system that is least likely to leak
refrigerant into the building space that are being cooled:
1 - correct answer ✔✔ The suction pressure of a reciprocating compressor is 65 PSIG. The
discharge pressure of this compressor is 120 PSIG. The atmospheric is 14.7 PSI. The compression
ratio for the given condition is closest to:
Dry vapor above the saturation temperature - correct answer ✔✔ A superheated vapor is:
A faulty cooling tower water level controller - correct answer ✔✔ A refrigerant engineer verifies
that a condenser water pump is cavitating. Of the following, the most likely cause for this
condition is:
The water supply to the pump suction inlet is below the pump level - correct answer ✔✔ A
centrifugal water pump is known as a lift pump when the:
Evaporator superheat - correct answer ✔✔ A TXV is used to maintain constant:
Yes, this temp is too high for human comfort purposes - correct answer ✔✔ The chilled water
supply to the building is 55 deg F. If the chiller is being used for human comfort, should you be
concerned about this, and why?
The drip part of the packing gland gives evidence that there is water in the pump - correct
answer ✔✔ The packing gland of a centrifugal pump serves to:
Operation of the hot gas bypass valve - correct answer ✔✔ Capacity control of reciprocating
hermetic compressor is typically achieved through:
A pure liquid refrigerant will enter the metering device - correct answer ✔✔ The most
important reason to sub-cool the refrigerant in the condenser is to ensure that:
, An expansion valve that is open too wide - correct answer ✔✔ A refrigeration engineer is
logging readings 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?
The level of the refrigerant in the evaporator - correct answer ✔✔ A low side float valve is used
to maintain:
A1 - correct answer ✔✔ Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower toxicity?
Only superheated vapor - correct answer ✔✔ When an expansion valve is operating properly, at
the end of the evaporator will contain:
Cost of the material - correct answer ✔✔ What information is not contained in a Material Safety
Data Sheet?
Maintain axial positioning of the rotor shaft - correct answer ✔✔ In a steam turbine, what is the
function of the Kingsbury thrust bearing?
The pump is full of liquid - correct answer ✔✔ A centrifugal water pump is considered to the
fully primed when?
Level type tubing bender - correct answer ✔✔ 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?
and answers
Lowering the condensing pressure - correct answer ✔✔ Efficiency of the refrigerant cycle is
affected by the operations of the condenser. Of the following, a more efficient centrifugal
compressor operation results from:
Sensible and latent heat - correct answer ✔✔ The heat removed from the refrigerant in a
condenser is:
Are approved by the US Dept. of Transportation - correct answer ✔✔ 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 NYC Fire
Code, you must ensure that the containers:
Keep in the suction valve opened while the compressor is in the return stroke - correct answer
✔✔ Which of the following best describes how the cylinder unloader works?
Cool the motor - correct answer ✔✔ In most semi-hermetic compressors, the suction vapor is
used to:
Differences between the high side and low side pressure - correct answer ✔✔ The amount of
refrigerant that flows through the orifices of an economizer is determined by the:
To remove impurities from the system - correct answer ✔✔ The installation of an inline
refrigerant cleaning system is advisable:
,Indirect system - correct answer ✔✔ The type of refrigerant system that is least likely to leak
refrigerant into the building space that are being cooled:
1 - correct answer ✔✔ The suction pressure of a reciprocating compressor is 65 PSIG. The
discharge pressure of this compressor is 120 PSIG. The atmospheric is 14.7 PSI. The compression
ratio for the given condition is closest to:
Dry vapor above the saturation temperature - correct answer ✔✔ A superheated vapor is:
A faulty cooling tower water level controller - correct answer ✔✔ A refrigerant engineer verifies
that a condenser water pump is cavitating. Of the following, the most likely cause for this
condition is:
The water supply to the pump suction inlet is below the pump level - correct answer ✔✔ A
centrifugal water pump is known as a lift pump when the:
Evaporator superheat - correct answer ✔✔ A TXV is used to maintain constant:
Yes, this temp is too high for human comfort purposes - correct answer ✔✔ The chilled water
supply to the building is 55 deg F. If the chiller is being used for human comfort, should you be
concerned about this, and why?
The drip part of the packing gland gives evidence that there is water in the pump - correct
answer ✔✔ The packing gland of a centrifugal pump serves to:
Operation of the hot gas bypass valve - correct answer ✔✔ Capacity control of reciprocating
hermetic compressor is typically achieved through:
A pure liquid refrigerant will enter the metering device - correct answer ✔✔ The most
important reason to sub-cool the refrigerant in the condenser is to ensure that:
, An expansion valve that is open too wide - correct answer ✔✔ A refrigeration engineer is
logging readings 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?
The level of the refrigerant in the evaporator - correct answer ✔✔ A low side float valve is used
to maintain:
A1 - correct answer ✔✔ Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower toxicity?
Only superheated vapor - correct answer ✔✔ When an expansion valve is operating properly, at
the end of the evaporator will contain:
Cost of the material - correct answer ✔✔ What information is not contained in a Material Safety
Data Sheet?
Maintain axial positioning of the rotor shaft - correct answer ✔✔ In a steam turbine, what is the
function of the Kingsbury thrust bearing?
The pump is full of liquid - correct answer ✔✔ A centrifugal water pump is considered to the
fully primed when?
Level type tubing bender - correct answer ✔✔ 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?
