FDNY Z51 WRITTEN EXAM 2024-
2025 LATEST UPDATED COMPLETE
350 QUESTIONS WITH DETAILED
VERIFIED AND 100% CORRECT
ANSWERS BRAND NEW EXAM
GRADED A+
If a sprinkler system is offline for two days, how often
do you need to inspect until it is returned to service?
A) 12-hours a day until system is restored.
B) Continuously, 24-hours a day until system is
restored.
C) Only in the evening, until restored.
D) Only in the morning, until restored. -
....ANSWER...B) Continuously, 24-hours a day until
system is restored.
Where is the muffler located?
A) After the condenser.
1
,B) Before the compressor.
C) Between the evaporator and condenser.
D) Between the compressor and condenser. -
....ANSWER...D) Between the compressor and condenser.
On an operating centrifugal compressor refrigerant unit,
the refrigeration engineer notices that the
compressor is short-cycling. The unit is using the
low-side float valve as a metering device. Of the
following requirements, this would indicate that
A) the system is undercharged with refrigerant.
B) the system is overcharged with refrigerant.
C) an inspection should be made for a dirty and
partially plugged discharge line.
D) the compressor wiring should be inspected. -
....ANSWER...A) the system is undercharged with
refrigerant.
2
,What should be done to prevent accidental activation of
smoke detectors during hot work operation?
A) Place fire alarm system out of service, notify the
Central Watch Station and provide fire watch.
B) Remove the batteries from the smoke detectors.
C) Cover the smoke detectors with plastic bags.
D) Inform the Central Station to ignore any fire alarm
signal during the hot work operation. -
....ANSWER...A) Place fire alarm system out of service,
notify the Central Watch Station and provide fire watch.
Under normal conditions, the refrigerant enters the
compressor as a
A) low-pressure, superheated vapor and leaves as a high-
pressure vapor.
B) high-temperature vapor and leaves as a low-
3
, pressure vapor.
C) low-pressure, superheated vapor and leaves as a high-
pressure, saturated liquid.
D) low-pressure vapor and leaves as a high- pressure
saturated vapor. - ....ANSWER...A) low- pressure,
superheated vapor and leaves as a high- pressure vapor.
The total amount of heat to be removed from the
refrigerant in a condenser equals the heat picked up in
the
A) evaporator plus the heat of compression.
B) evaporator.
C) evaporator less the heat given up in the muffler.
4
2025 LATEST UPDATED COMPLETE
350 QUESTIONS WITH DETAILED
VERIFIED AND 100% CORRECT
ANSWERS BRAND NEW EXAM
GRADED A+
If a sprinkler system is offline for two days, how often
do you need to inspect until it is returned to service?
A) 12-hours a day until system is restored.
B) Continuously, 24-hours a day until system is
restored.
C) Only in the evening, until restored.
D) Only in the morning, until restored. -
....ANSWER...B) Continuously, 24-hours a day until
system is restored.
Where is the muffler located?
A) After the condenser.
1
,B) Before the compressor.
C) Between the evaporator and condenser.
D) Between the compressor and condenser. -
....ANSWER...D) Between the compressor and condenser.
On an operating centrifugal compressor refrigerant unit,
the refrigeration engineer notices that the
compressor is short-cycling. The unit is using the
low-side float valve as a metering device. Of the
following requirements, this would indicate that
A) the system is undercharged with refrigerant.
B) the system is overcharged with refrigerant.
C) an inspection should be made for a dirty and
partially plugged discharge line.
D) the compressor wiring should be inspected. -
....ANSWER...A) the system is undercharged with
refrigerant.
2
,What should be done to prevent accidental activation of
smoke detectors during hot work operation?
A) Place fire alarm system out of service, notify the
Central Watch Station and provide fire watch.
B) Remove the batteries from the smoke detectors.
C) Cover the smoke detectors with plastic bags.
D) Inform the Central Station to ignore any fire alarm
signal during the hot work operation. -
....ANSWER...A) Place fire alarm system out of service,
notify the Central Watch Station and provide fire watch.
Under normal conditions, the refrigerant enters the
compressor as a
A) low-pressure, superheated vapor and leaves as a high-
pressure vapor.
B) high-temperature vapor and leaves as a low-
3
, pressure vapor.
C) low-pressure, superheated vapor and leaves as a high-
pressure, saturated liquid.
D) low-pressure vapor and leaves as a high- pressure
saturated vapor. - ....ANSWER...A) low- pressure,
superheated vapor and leaves as a high- pressure vapor.
The total amount of heat to be removed from the
refrigerant in a condenser equals the heat picked up in
the
A) evaporator plus the heat of compression.
B) evaporator.
C) evaporator less the heat given up in the muffler.
4
