FDNY Z51 EXAM BANK | 2025 COMPLETE FDNY Z-
51 ACCURATE REAL EXAM QUESTIONS WITH
DETAILED ANSWERS | ALREADY GRADED A+ |
GUARANTEED EXCELLENCE PASS
A water pump is discharge against head 92 feet of water this is approximately to a
pressure of: - ✔✔✔ Correct Answer > 40 psi
What is the function of the vacuum breaker in a steam turbine. - ✔✔✔ Correct
Answer > To achieve a faster coast down cycle
Which of the following best describes how the cylinder unloader work? - ✔✔✔
Correct Answer > Keep in the suction valve opened while the compressor is in
the return stroke
An equalizer line on a TXV is used to: - ✔✔✔ Correct Answer > Compensate for
the pressure drop across the evaporator coil
If R134 accidentally touches a refrigerant engineer's skin, what first aid should be
applied from the MSDS? - ✔✔✔ Correct Answer > Promptly flush skin with water
until all chemical is removed
In a multi stage centrifugal compressor, each stage: - ✔✔✔ Correct Answer > Is
identical in volume to the other stages
,Which of the following will connect to the middle port on a gauge manifold? -
✔✔✔ Correct Answer > Vacuum pump
The most important reason for installing a muffler in a reciprocating refrigerant
machine is: - ✔✔✔ Correct Answer > To contain the compressor pulsation noise
In most semi hermetic compressors, the suction vapor is used to: - ✔✔✔ Correct
Answer > Cool the motor
The amount of refrigerant that flows through the orifices of a economizer is
determined by the: - ✔✔✔ Correct Answer > Difference between the high side
and load side pressure
The installation of an inline refrigerant cleaning system is advisable: - ✔✔✔
Correct 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 cooled - ✔✔✔ Correct Answer > The indirect system
The suction pressure of a reciprocating compressor is 65PSIG. the discharge
pressure of this compressor is 120PSIG. the atmospheric is 14.7 PSI. the
compression ratio for the given condition is closet to: - ✔✔✔ Correct Answer >
1.69
A super-heated vapor is a? - ✔✔✔ Correct 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: - ✔✔✔ Correct Answer > A
faulty cooling tower water level controller
A centrifugal water pump is known as a lift pump when the: - ✔✔✔ Correct
Answer > The water supply to the pump suction inlet is below the pump level
A TXV is used to maintain constant: - ✔✔✔ Correct Answer > Evaporator
superheat
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? - ✔✔✔ Correct
Answer > Yes, this temperature is too high for human comfort purpose
The packing gland of a centrifugal pump serves to: - ✔✔✔ Correct Answer > 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 - ✔✔✔ Correct Answer > Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to
ensure that: - ✔✔✔ Correct Answer > A pure liquid refrigerant will enter the
metering device
A refrigeration engineer is logging reading from a reciprocating system.
compressor discharge temperature has dropped significantly and the suction line
pressure is high. which of the following that may be causing this set of condition. -
✔✔✔ Correct Answer > An expansion valve that is open to wide
51 ACCURATE REAL EXAM QUESTIONS WITH
DETAILED ANSWERS | ALREADY GRADED A+ |
GUARANTEED EXCELLENCE PASS
A water pump is discharge against head 92 feet of water this is approximately to a
pressure of: - ✔✔✔ Correct Answer > 40 psi
What is the function of the vacuum breaker in a steam turbine. - ✔✔✔ Correct
Answer > To achieve a faster coast down cycle
Which of the following best describes how the cylinder unloader work? - ✔✔✔
Correct Answer > Keep in the suction valve opened while the compressor is in
the return stroke
An equalizer line on a TXV is used to: - ✔✔✔ Correct Answer > Compensate for
the pressure drop across the evaporator coil
If R134 accidentally touches a refrigerant engineer's skin, what first aid should be
applied from the MSDS? - ✔✔✔ Correct Answer > Promptly flush skin with water
until all chemical is removed
In a multi stage centrifugal compressor, each stage: - ✔✔✔ Correct Answer > Is
identical in volume to the other stages
,Which of the following will connect to the middle port on a gauge manifold? -
✔✔✔ Correct Answer > Vacuum pump
The most important reason for installing a muffler in a reciprocating refrigerant
machine is: - ✔✔✔ Correct Answer > To contain the compressor pulsation noise
In most semi hermetic compressors, the suction vapor is used to: - ✔✔✔ Correct
Answer > Cool the motor
The amount of refrigerant that flows through the orifices of a economizer is
determined by the: - ✔✔✔ Correct Answer > Difference between the high side
and load side pressure
The installation of an inline refrigerant cleaning system is advisable: - ✔✔✔
Correct 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 cooled - ✔✔✔ Correct Answer > The indirect system
The suction pressure of a reciprocating compressor is 65PSIG. the discharge
pressure of this compressor is 120PSIG. the atmospheric is 14.7 PSI. the
compression ratio for the given condition is closet to: - ✔✔✔ Correct Answer >
1.69
A super-heated vapor is a? - ✔✔✔ Correct 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: - ✔✔✔ Correct Answer > A
faulty cooling tower water level controller
A centrifugal water pump is known as a lift pump when the: - ✔✔✔ Correct
Answer > The water supply to the pump suction inlet is below the pump level
A TXV is used to maintain constant: - ✔✔✔ Correct Answer > Evaporator
superheat
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? - ✔✔✔ Correct
Answer > Yes, this temperature is too high for human comfort purpose
The packing gland of a centrifugal pump serves to: - ✔✔✔ Correct Answer > 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 - ✔✔✔ Correct Answer > Operation of the hot gas bypass valve
The most important reason to sub-cool the refrigerant in the condenser is to
ensure that: - ✔✔✔ Correct Answer > A pure liquid refrigerant will enter the
metering device
A refrigeration engineer is logging reading from a reciprocating system.
compressor discharge temperature has dropped significantly and the suction line
pressure is high. which of the following that may be causing this set of condition. -
✔✔✔ Correct Answer > An expansion valve that is open to wide
