Page |1
Z-51 WRITTEN EXAM 2025| BRAND NEW
ACTUAL EXAM WITH 100% VERIFIED
QUESTIONS AND CORRECT SOLUTIONS|
GUARANTEED VALUE PACK| ACE YOUR
GRADES.
In an office building, the display of cut natural trees (Christmas trees) is
A) never allowed.
B) allowed provided they are removed once they dry out.
C) always allowed.
D) allowed during the holiday season. - correct answer - A) never allowed.
Describe the equipment's function in the picture.
A) Control flow of refrigerant to the compressor.
B) Remove non-condensable from the condenser.
C) Relieve excess pressure from the condenser.
D) Relieve excess pressure from the evaporator. - correct answer - B)
Remove non-condensable from the condenser.
, Page |2
When the expansion valve is operating properly, the end of the evaporator
will contain
A) only superheated vapor.
B) saturated liquid refrigerant
C) only vapor.
D) only liquid refrigerant. - correct answer - A) only superheated vapor.
How much extra refrigerant con be stored in a machine room?
A) 330 lbs.
B) The amount equal to the design pressure.
C) 20% above normal charge.
D) 220 lbs. - correct answer - C) 20% above normal charge.
A refrigeration compressor has failed to turn on. The refrigeration engineer
on duty verifies that the electrical circuit to the motor, including all switches
and circuit breakers, is complete according to recommended service
practice. The next item to be checked would likely by the
A) temperature and pressure controls.
B) refrigerant charge.
C) cooling tower operation.
D) liquid-line solenoid valve. - correct answer - A) temperature and
pressure controls.
, Page |3
The use of oil in the refrigeration machine is to
A) Add non-condensates to refrigerant.
B) Mix the oil with liquid refrigerant.
C) Reduce wear and friction in compressor parts.
D) None of the answers are correct. - correct answer - C) Reduce wear and
friction in compressor parts.
The heat removed from the refrigerant condenser is
A) latent heat only.
B) sensible heat only.
C) sensible and latent heat.
D) Radiant heat only. - correct answer - C) sensible and latent heat.
Which service valve should be installed in a dual pressure release valve
while keeping system in service?
A) Two-way valve.
B) Plug valve.
C) Three-way valve.
D) Stop valve. - correct answer - C) Three-way valve.
, Page |4
The monthly quick check of a fire extinguisher does NOT include
A) Checking the extinguisher for damage.
B) Confirming its proper location.
C) Discharging the extinguisher.
D) Ensuring it is clear from any obstructions. - correct answer - C)
Discharging the extinguisher.
Several components of a sprinkler system in an office building need to be
repaired. Which of the following are allowed to perform the repair work?
A) A Q-01 refrigeration engineer holding S-12 CoF.
B) A Master Fire Suppression Contractor holding S-12 CoF.
C) Any Master Fire Suppression Piping Contractor.
D) A S-12 CoF holder without any other license. - correct answer - B) A
Master Fire Suppression Contractor holding S-12 CoF.
A FDNY permit is required to conduct hot work for
A) brazing.
B) welding.
C) use of oxygen and flammable gas.
Z-51 WRITTEN EXAM 2025| BRAND NEW
ACTUAL EXAM WITH 100% VERIFIED
QUESTIONS AND CORRECT SOLUTIONS|
GUARANTEED VALUE PACK| ACE YOUR
GRADES.
In an office building, the display of cut natural trees (Christmas trees) is
A) never allowed.
B) allowed provided they are removed once they dry out.
C) always allowed.
D) allowed during the holiday season. - correct answer - A) never allowed.
Describe the equipment's function in the picture.
A) Control flow of refrigerant to the compressor.
B) Remove non-condensable from the condenser.
C) Relieve excess pressure from the condenser.
D) Relieve excess pressure from the evaporator. - correct answer - B)
Remove non-condensable from the condenser.
, Page |2
When the expansion valve is operating properly, the end of the evaporator
will contain
A) only superheated vapor.
B) saturated liquid refrigerant
C) only vapor.
D) only liquid refrigerant. - correct answer - A) only superheated vapor.
How much extra refrigerant con be stored in a machine room?
A) 330 lbs.
B) The amount equal to the design pressure.
C) 20% above normal charge.
D) 220 lbs. - correct answer - C) 20% above normal charge.
A refrigeration compressor has failed to turn on. The refrigeration engineer
on duty verifies that the electrical circuit to the motor, including all switches
and circuit breakers, is complete according to recommended service
practice. The next item to be checked would likely by the
A) temperature and pressure controls.
B) refrigerant charge.
C) cooling tower operation.
D) liquid-line solenoid valve. - correct answer - A) temperature and
pressure controls.
, Page |3
The use of oil in the refrigeration machine is to
A) Add non-condensates to refrigerant.
B) Mix the oil with liquid refrigerant.
C) Reduce wear and friction in compressor parts.
D) None of the answers are correct. - correct answer - C) Reduce wear and
friction in compressor parts.
The heat removed from the refrigerant condenser is
A) latent heat only.
B) sensible heat only.
C) sensible and latent heat.
D) Radiant heat only. - correct answer - C) sensible and latent heat.
Which service valve should be installed in a dual pressure release valve
while keeping system in service?
A) Two-way valve.
B) Plug valve.
C) Three-way valve.
D) Stop valve. - correct answer - C) Three-way valve.
, Page |4
The monthly quick check of a fire extinguisher does NOT include
A) Checking the extinguisher for damage.
B) Confirming its proper location.
C) Discharging the extinguisher.
D) Ensuring it is clear from any obstructions. - correct answer - C)
Discharging the extinguisher.
Several components of a sprinkler system in an office building need to be
repaired. Which of the following are allowed to perform the repair work?
A) A Q-01 refrigeration engineer holding S-12 CoF.
B) A Master Fire Suppression Contractor holding S-12 CoF.
C) Any Master Fire Suppression Piping Contractor.
D) A S-12 CoF holder without any other license. - correct answer - B) A
Master Fire Suppression Contractor holding S-12 CoF.
A FDNY permit is required to conduct hot work for
A) brazing.
B) welding.
C) use of oxygen and flammable gas.
