FDNY Z-51 REFRIGERATION TEST 2025
QUESTIONS| WITH ALREADY SOLVED
CORRECTLY ANSWERS!! | ASSURED
SUCCESS
Efficiency of the refrigerant cycle is affected by the operations 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 NYC Fire Code, you
must ensure that the containers: - 🧠ANSWER ✔✔Are approved by the US
Dept. of Transportation
Which of the following best describes how the cylinder unloader works? -
🧠ANSWER ✔✔Keep in the suction valve opened while the compressor is in
the return stroke
1
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,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 an economizer
is determined by the: - 🧠ANSWER ✔✔Differences between the high side
and low 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 being cooled: - 🧠ANSWER ✔✔Indirect system
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: -
🧠ANSWER ✔✔1.69
A superheated vapor is: - 🧠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
2
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,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 55 deg F. If the chiller is being
used for human comfort, should you be concerned about this, and why? -
🧠ANSWER ✔✔Yes, this temp is too high for human comfort purposes
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 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 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
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, this set of condition? - 🧠ANSWER ✔✔An expansion valve that is open too
wide
A low side float valve is used to maintain: - 🧠ANSWER ✔✔The level of the
refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower 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? -
🧠ANSWER ✔✔Cost of the 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 the 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
4
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
QUESTIONS| WITH ALREADY SOLVED
CORRECTLY ANSWERS!! | ASSURED
SUCCESS
Efficiency of the refrigerant cycle is affected by the operations 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 NYC Fire Code, you
must ensure that the containers: - 🧠ANSWER ✔✔Are approved by the US
Dept. of Transportation
Which of the following best describes how the cylinder unloader works? -
🧠ANSWER ✔✔Keep in the suction valve opened while the compressor is in
the return stroke
1
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,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 an economizer
is determined by the: - 🧠ANSWER ✔✔Differences between the high side
and low 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 being cooled: - 🧠ANSWER ✔✔Indirect system
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: -
🧠ANSWER ✔✔1.69
A superheated vapor is: - 🧠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
2
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,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 55 deg F. If the chiller is being
used for human comfort, should you be concerned about this, and why? -
🧠ANSWER ✔✔Yes, this temp is too high for human comfort purposes
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 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 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
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, this set of condition? - 🧠ANSWER ✔✔An expansion valve that is open too
wide
A low side float valve is used to maintain: - 🧠ANSWER ✔✔The level of the
refrigerant in the evaporator
Regarding fire safety, which ASHRAE refrigerant safety classification
indicates no flammability and lower 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? -
🧠ANSWER ✔✔Cost of the 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 the 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
4
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
