FDNY Z51/ Z-51 REFRIGERATION EXAM TEST ACTUAL EXAM
Z-51 REFRIGERATION TEST
QUESTIONS AND CORRECT DETAILED ANSWERS |ALREADY
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GRADED A+
1. Efficiency of the refrigerant cycle is affected by the Lowering the condensing
operations of the condenser. Of the following, a pressure
more efficient centrifugal compressor operation re-
sults from:
2. The heat removed from the refrigerant in a condenser Sensible and latent heat
is:
3. The refrigerant unit that you have been assigned to is Are approved by the US
being taken out of service for a major repair. You have Dept. of Transportation
been assigned to withdraw refrigerant for storage in
suitable containers. According to the NYC Fire Code,
you must ensure that the containers:
4. Which of the following best describes how the cylinder Keep in the suction valve
unloader works? opened while the com-
pressor is in the return
stroke
5. In most semi-hermetic compressors, the suction va- Cool the motor
por is used to:
6. The amount of refrigerant that flows through the ori- Differences between the
fices of an economizer is determined by the: high side and low side
pressure
7. The installation of an inline refrigerant cleaning sys- To remove impurities from
tem is advisable: the system
8. The type of refrigerant system that is least likely to Indirect system
leak refrigerant into the building space that are being
cooled:
, Z-51 REFRIGERATION TEST
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9. The suction pressure of a reciprocating compressor is 1.69
65 PSIG. The discharge pressure of this compressor is
120 PSIG. The atmospheric is 14.7 PSI. The compres-
sion ratio for the given condition is closest to:
10. A superheated vapor is: Dry vapor above the satu-
ration temperature
11. A refrigerant engineer verifies that a condenser water A faulty cooling tower wa-
pump is cavitating. Of the following, the most likely ter level controller
cause for this condition is:
12. A centrifugal water pump is known as a lift pump The water supply to the
when the: pump suction inlet is be-
low the pump level
13. A TXV is used to maintain constant: Evaporator superheat
14. The chilled water supply to the building is 55 deg F. If Yes, this temp is too high
the chiller is being used for human comfort, should for human comfort pur-
you be concerned about this, and why? poses
15. The packing gland of a centrifugal pump serves to: The drip part of the pack-
ing gland gives evidence
that there is water in the
pump
16. Capacity control of reciprocating hermetic compres- Operation of the hot gas
sor is typically achieved through: bypass valve
17. The most important reason to sub-cool the refrigerant A pure liquid refrigerant
in the condenser is to ensure that: will enter the metering
device
, Z-51 REFRIGERATION TEST
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18. A refrigeration engineer is logging readings from a An expansion valve that is
reciprocating system. Compressor discharge temper- open too wide
ature have dropped significantly and the suction line
pressure is high. Which of the following that may be
causing this set of condition?
19. A low side float valve is used to maintain: The level of the refrigerant
in the evaporator
20. Regarding fire safety, which ASHRAE refrigerant safety A1
classification indicates no flammability and lower tox-
icity?
21. When an expansion valve is operating properly, at the Only superheated vapor
end of the evaporator will contain:
22. What information is not contained in a Material Safety Cost of the material
Data Sheet?
23. In a steam turbine, what is the function of the Kings- Maintain axial positioning
bury thrust bearing? of the rotor shaft
24. A centrifugal water pump is considered to the fully The pump is full of liquid
primed when?
25. Copper tubing refrigerant lines must be installed for Level type tubing bender
a new system. It is a well known service practice that
tubing collapses at bends that must be made, the
refrigerant engineer should use?
26. A reciprocating compressor is making a knocking Slugging of the liquid re-
sound during operation. If the refrigerant worn parts frigerant
are not causing the knocking, what probably the
cause?
Z-51 REFRIGERATION TEST
QUESTIONS AND CORRECT DETAILED ANSWERS |ALREADY
Study online at https://quizlet.com/_hj8l9t
GRADED A+
1. Efficiency of the refrigerant cycle is affected by the Lowering the condensing
operations of the condenser. Of the following, a pressure
more efficient centrifugal compressor operation re-
sults from:
2. The heat removed from the refrigerant in a condenser Sensible and latent heat
is:
3. The refrigerant unit that you have been assigned to is Are approved by the US
being taken out of service for a major repair. You have Dept. of Transportation
been assigned to withdraw refrigerant for storage in
suitable containers. According to the NYC Fire Code,
you must ensure that the containers:
4. Which of the following best describes how the cylinder Keep in the suction valve
unloader works? opened while the com-
pressor is in the return
stroke
5. In most semi-hermetic compressors, the suction va- Cool the motor
por is used to:
6. The amount of refrigerant that flows through the ori- Differences between the
fices of an economizer is determined by the: high side and low side
pressure
7. The installation of an inline refrigerant cleaning sys- To remove impurities from
tem is advisable: the system
8. The type of refrigerant system that is least likely to Indirect system
leak refrigerant into the building space that are being
cooled:
, Z-51 REFRIGERATION TEST
Study online at https://quizlet.com/_hj8l9t
9. The suction pressure of a reciprocating compressor is 1.69
65 PSIG. The discharge pressure of this compressor is
120 PSIG. The atmospheric is 14.7 PSI. The compres-
sion ratio for the given condition is closest to:
10. A superheated vapor is: Dry vapor above the satu-
ration temperature
11. A refrigerant engineer verifies that a condenser water A faulty cooling tower wa-
pump is cavitating. Of the following, the most likely ter level controller
cause for this condition is:
12. A centrifugal water pump is known as a lift pump The water supply to the
when the: pump suction inlet is be-
low the pump level
13. A TXV is used to maintain constant: Evaporator superheat
14. The chilled water supply to the building is 55 deg F. If Yes, this temp is too high
the chiller is being used for human comfort, should for human comfort pur-
you be concerned about this, and why? poses
15. The packing gland of a centrifugal pump serves to: The drip part of the pack-
ing gland gives evidence
that there is water in the
pump
16. Capacity control of reciprocating hermetic compres- Operation of the hot gas
sor is typically achieved through: bypass valve
17. The most important reason to sub-cool the refrigerant A pure liquid refrigerant
in the condenser is to ensure that: will enter the metering
device
, Z-51 REFRIGERATION TEST
Study online at https://quizlet.com/_hj8l9t
18. A refrigeration engineer is logging readings from a An expansion valve that is
reciprocating system. Compressor discharge temper- open too wide
ature have dropped significantly and the suction line
pressure is high. Which of the following that may be
causing this set of condition?
19. A low side float valve is used to maintain: The level of the refrigerant
in the evaporator
20. Regarding fire safety, which ASHRAE refrigerant safety A1
classification indicates no flammability and lower tox-
icity?
21. When an expansion valve is operating properly, at the Only superheated vapor
end of the evaporator will contain:
22. What information is not contained in a Material Safety Cost of the material
Data Sheet?
23. In a steam turbine, what is the function of the Kings- Maintain axial positioning
bury thrust bearing? of the rotor shaft
24. A centrifugal water pump is considered to the fully The pump is full of liquid
primed when?
25. Copper tubing refrigerant lines must be installed for Level type tubing bender
a new system. It is a well known service practice that
tubing collapses at bends that must be made, the
refrigerant engineer should use?
26. A reciprocating compressor is making a knocking Slugging of the liquid re-
sound during operation. If the refrigerant worn parts frigerant
are not causing the knocking, what probably the
cause?
