Z-51 WRITTEN EXAM 2024
ANSWER ALL QUESTIONS IN THIS SECTION
QUESTION 1
The sole refrigeration engineer on duty in a building is permitted to leave the
building refrigeration system when it is in operation when:
A. Lunch or dinner occur
B. System is an automatic operation
C. Relieved by another licensed refrigeration engineer
D. The assistant provides coverage or supervision - ANSWERS-C. Relieved by
another licensed refrigeration engineer
QUESTION 2
A system controlled by a TXV show high discharge pressure and high normal sub-
cooling. the cause is most probably a:
A. Superheat settings that has been set incorrectly
B. Refrigerant overcharge
C. Leaking compressor discharge valve
D. Low system amperage draw - ANSWERS-B. Refrigerant overcharge
END OF
PAGE 1
, Z-51 WRITTEN EXAM 2024
QUESTION 3
Which of the following is a correct statement?
A. 2.5 gallon of water weight 10.7 pounds
B. 2.5 gallon of water weight 1.05
C. 2.5 gallons of water weight 20.8 pounds
D. 2.5 gallon of water 2.5 cubic feet - ANSWERS-C. 2.5 gallons of water weight
20.8 pounds
QUESTION 4
Liquid level gauge glasses (except the bull's eye) are generally equipped with:
A. Manual and automatic closing shut-off valve
B. Manual shut-off valves only
C. Automatic shut-off valves only
D. Either manual or autonomic closing shut-off valve - ANSWERS-C. Automatic
shut-off valves only
QUESTION 5
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PAGE 2
, Z-51 WRITTEN EXAM 2024
Copper and aluminum are frequently used for condenser tubes in refrigeration
system. these metals are used because of their:
A. Easy availability
B. High heat transfer coefficient
C. Resistance to corrosion
D. Resistance to failing - ANSWERS-B. High heat transfer coefficient
QUESTION 6
Assume that a refrigeration engineer has a choice of four valves to select from.
Which of the following is the most effective type of valve to control pressure?
A. Ball valve
B. Quarter turn valve
C. Gate valve
D. Plug valve - ANSWERS-D. Plug valve
QUESTION 7
Where must the material safety data sheet be located?
END OF
PAGE 3
, Z-51 WRITTEN EXAM 2024
A. Near the entrance to the machine room
B. Where flammable liquids are used
C. Where available to all employees
D. Where any toxic material is used - ANSWERS-C. Where available to all
employees
QUESTION 8
The oil collected in an oil separator is generally:
A. Drained and replaced with fresh oil
B. Filtered and returned to the compressor
C. Caused by oil overcharge
D. Returned to the compressor - ANSWERS-D. Returned to the compressor
What is the function of the gland steam?
A. Prevent foaming in oil pump
B. Heat the bearing oil before start up
END OF
PAGE 4
ANSWER ALL QUESTIONS IN THIS SECTION
QUESTION 1
The sole refrigeration engineer on duty in a building is permitted to leave the
building refrigeration system when it is in operation when:
A. Lunch or dinner occur
B. System is an automatic operation
C. Relieved by another licensed refrigeration engineer
D. The assistant provides coverage or supervision - ANSWERS-C. Relieved by
another licensed refrigeration engineer
QUESTION 2
A system controlled by a TXV show high discharge pressure and high normal sub-
cooling. the cause is most probably a:
A. Superheat settings that has been set incorrectly
B. Refrigerant overcharge
C. Leaking compressor discharge valve
D. Low system amperage draw - ANSWERS-B. Refrigerant overcharge
END OF
PAGE 1
, Z-51 WRITTEN EXAM 2024
QUESTION 3
Which of the following is a correct statement?
A. 2.5 gallon of water weight 10.7 pounds
B. 2.5 gallon of water weight 1.05
C. 2.5 gallons of water weight 20.8 pounds
D. 2.5 gallon of water 2.5 cubic feet - ANSWERS-C. 2.5 gallons of water weight
20.8 pounds
QUESTION 4
Liquid level gauge glasses (except the bull's eye) are generally equipped with:
A. Manual and automatic closing shut-off valve
B. Manual shut-off valves only
C. Automatic shut-off valves only
D. Either manual or autonomic closing shut-off valve - ANSWERS-C. Automatic
shut-off valves only
QUESTION 5
END OF
PAGE 2
, Z-51 WRITTEN EXAM 2024
Copper and aluminum are frequently used for condenser tubes in refrigeration
system. these metals are used because of their:
A. Easy availability
B. High heat transfer coefficient
C. Resistance to corrosion
D. Resistance to failing - ANSWERS-B. High heat transfer coefficient
QUESTION 6
Assume that a refrigeration engineer has a choice of four valves to select from.
Which of the following is the most effective type of valve to control pressure?
A. Ball valve
B. Quarter turn valve
C. Gate valve
D. Plug valve - ANSWERS-D. Plug valve
QUESTION 7
Where must the material safety data sheet be located?
END OF
PAGE 3
, Z-51 WRITTEN EXAM 2024
A. Near the entrance to the machine room
B. Where flammable liquids are used
C. Where available to all employees
D. Where any toxic material is used - ANSWERS-C. Where available to all
employees
QUESTION 8
The oil collected in an oil separator is generally:
A. Drained and replaced with fresh oil
B. Filtered and returned to the compressor
C. Caused by oil overcharge
D. Returned to the compressor - ANSWERS-D. Returned to the compressor
What is the function of the gland steam?
A. Prevent foaming in oil pump
B. Heat the bearing oil before start up
END OF
PAGE 4
