age 1 of 60
,age 2 of 60
FDNY Z-51 REFRIGERATION EXAM
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
,age 3 of 60
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
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
, age 4 of 60
The suction pressure of a reciprocating compressor is 65 PSIG. The
j j j j j j j j j j
discharge pressure of this compressor is 120 PSIG. The
j j j j j j j j j
atmospheric is 14.7 PSI. The compression ratio for the given
j j j j j j j j j j
condition is closest to: .......Answer. .......... 1.69
j j j j j
A superheated vapor is: .......Answer.........Dry vapor above the
j j j j j j j
saturation temperature
j j
A refrigerant engineer verifies that a condenser water pump is
j j j j j j j j j
cavitating. Of the following, the most likely cause for this condition is:
j j j j j j j j j j j j
.......Answer.........A faulty cooling tower water level controller
j j j j j j j
A centrifugal water pump is known as a lift pump when the:
j j j j j j j j j j j
.......Answer.........The water supply to the pump suction inlet is below the j j j j j j j j j j
pump level
j j
,age 2 of 60
FDNY Z-51 REFRIGERATION EXAM
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
,age 3 of 60
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
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
, age 4 of 60
The suction pressure of a reciprocating compressor is 65 PSIG. The
j j j j j j j j j j
discharge pressure of this compressor is 120 PSIG. The
j j j j j j j j j
atmospheric is 14.7 PSI. The compression ratio for the given
j j j j j j j j j j
condition is closest to: .......Answer. .......... 1.69
j j j j j
A superheated vapor is: .......Answer.........Dry vapor above the
j j j j j j j
saturation temperature
j j
A refrigerant engineer verifies that a condenser water pump is
j j j j j j j j j
cavitating. Of the following, the most likely cause for this condition is:
j j j j j j j j j j j j
.......Answer.........A faulty cooling tower water level controller
j j j j j j j
A centrifugal water pump is known as a lift pump when the:
j j j j j j j j j j j
.......Answer.........The water supply to the pump suction inlet is below the j j j j j j j j j j
pump level
j j
