FDNY Z-51 Written Exam 2025/2026
Exam Questions and Correct Answers |
New Update
The efficiency of the refrigerant cycle is affected by the operation of the
condenser. Of the following, a more efficient centrifugal compressor
operation results from:
A. Raising the condenser liquid level to the maximum
B. Lowering the chilled water set point
C. Raising the condenser head pressure
D. Lowering the condensing pressure - 🧠ANSWER ✔✔D. Lowering the
condensing pressure
The heat removed from the refrigerant in a condenser is:
A. Sensible and latent heat
B. Latent heat only
1
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,C. Radiant heat only
D. Sensible heat only - 🧠ANSWER ✔✔A. 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 New York City fire code,
you must ensure that the containers:
A. Do not weigh more than 200 pounds when filled
B. Are approved by the US Department of Transportation
C. Are approved by the OSHA Association
D. Do not exceed 55 Gallons in capacity - 🧠ANSWER ✔✔B. Are approved
by the US Department of Transportation
Which of the following best describes how the cylinder unloader work?
A. Keep in the suction valve opened while the compressor is in the return
stroke
B. Controls the clearance volume in the compressor with a solenoid
2
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,C. Controls the opening of the passage into the compressor with variable
vanes
D. Unloads the piston to create less pressure - 🧠ANSWER ✔✔A. Keep in
the suction valve opened while the compressor is in the return stroke
In the most semi Hermetic compressors, the suction vapor is used to:
A. Removes oil from the motor housing
B. Cools the motor
C. Minimizes oil foaming
D. Removes oil foam from the shaft - 🧠ANSWER ✔✔B. Cools the motor
The amount of refrigerant that flows through the orifices of a economizer is
determined by the:
A. Number of economizer stages
B. Temperature of the high side refrigerant
C. Number of compressor stages
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, D. Difference between high side and low side pressure - 🧠ANSWER ✔✔D.
Difference between high side and low side pressure
The installation of an inline refrigerant cleaning system is advisable:
A. For high pressure refrigerant systems
B. To purge non-condensables
C. For systems using toxic refrigerant
D. To remove impurities from the system - 🧠ANSWER ✔✔D. 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:
A. The direct vented closed system
B. The direct closed system
C. Any system using reciprocating compressor
D. The indirect system - 🧠ANSWER ✔✔D. The indirect system
4
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
Exam Questions and Correct Answers |
New Update
The efficiency of the refrigerant cycle is affected by the operation of the
condenser. Of the following, a more efficient centrifugal compressor
operation results from:
A. Raising the condenser liquid level to the maximum
B. Lowering the chilled water set point
C. Raising the condenser head pressure
D. Lowering the condensing pressure - 🧠ANSWER ✔✔D. Lowering the
condensing pressure
The heat removed from the refrigerant in a condenser is:
A. Sensible and latent heat
B. Latent heat only
1
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,C. Radiant heat only
D. Sensible heat only - 🧠ANSWER ✔✔A. 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 New York City fire code,
you must ensure that the containers:
A. Do not weigh more than 200 pounds when filled
B. Are approved by the US Department of Transportation
C. Are approved by the OSHA Association
D. Do not exceed 55 Gallons in capacity - 🧠ANSWER ✔✔B. Are approved
by the US Department of Transportation
Which of the following best describes how the cylinder unloader work?
A. Keep in the suction valve opened while the compressor is in the return
stroke
B. Controls the clearance volume in the compressor with a solenoid
2
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
,C. Controls the opening of the passage into the compressor with variable
vanes
D. Unloads the piston to create less pressure - 🧠ANSWER ✔✔A. Keep in
the suction valve opened while the compressor is in the return stroke
In the most semi Hermetic compressors, the suction vapor is used to:
A. Removes oil from the motor housing
B. Cools the motor
C. Minimizes oil foaming
D. Removes oil foam from the shaft - 🧠ANSWER ✔✔B. Cools the motor
The amount of refrigerant that flows through the orifices of a economizer is
determined by the:
A. Number of economizer stages
B. Temperature of the high side refrigerant
C. Number of compressor stages
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
, D. Difference between high side and low side pressure - 🧠ANSWER ✔✔D.
Difference between high side and low side pressure
The installation of an inline refrigerant cleaning system is advisable:
A. For high pressure refrigerant systems
B. To purge non-condensables
C. For systems using toxic refrigerant
D. To remove impurities from the system - 🧠ANSWER ✔✔D. 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:
A. The direct vented closed system
B. The direct closed system
C. Any system using reciprocating compressor
D. The indirect system - 🧠ANSWER ✔✔D. The indirect system
4
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
