Z-51 EXAM QUESTIONS AND ANSWERS COMPLETE QUESTIONS WITH CORRECT ANSWERS RATED A+ UPDATED 2024/2025
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Course
Z51
Institution
Z51
Z-51 EXAM QUESTIONS AND ANSWERS
COMPLETE QUESTIONS WITH
CORRECT ANSWERS RATED A+
UPDATED 2024/2025
1. What can be said about the chilled water supply temperature of
55°? - ANSWER It is not ideal and frankly too high.
2. What is the compressor oil service valve used for? - ANSWER
It i...
Z-51 EXAM QUESTIONS AND ANSWERS
COMPLETE QUESTIONS WITH
CORRECT ANSWERS RATED A+
UPDATED 2024/2025
1. What can be said about the chilled water supply temperature of
55°? - ANSWER ✔ It is not ideal and frankly too high.
2. What is the compressor oil service valve used for? - ANSWER ✔
It is used to add and remove oil from the compressor crank case.
3. What components does the suction line tie together and connect? -
ANSWER ✔ The suction line connects the outlet of the
evaporator to the inlet side of the compressor this is also called the
low side or suction side.
4. In what form is the refrigerant on the suction line and what's the
average superheat in degrees? - ANSWER ✔ The refrigerant on
the suction line is a low-pressure vapor what's an average
superheated temperature of 7-12°.
5. What components does the liquid line tie together and connect? -
ANSWER ✔ The liquid line connects the outlet of the condenser
, to the metering device which is located on the inlet of the
evaporator.
6. What state is the refrigerant on the liquid line and to what degree is
it subcooled? - ANSWER ✔ The refrigerant on the liquid one is a
high pressure liquid subcooled about 10°.
7. What components does the discharge line tie together and connect?
- ANSWER ✔ The discharge line connects the outlet of the
compressor also called the high side or discharge side to the inlet
of the condenser.
8. At what state is the refrigerant on the discharge line and is it
superheated? - ANSWER ✔ The refrigerant on the discharge line
is a high-pressure vapor which is highly superheated. It enters as a
superheated vapor, picks up heat of compression in the compressor
and exits as a highly superheated vapor.
9. How many hot wires do three phase 460 or 480 V circuits have? -
ANSWER ✔ Three hot wires.
10. How many hot wires does a single phase 220 V circuit have?
- ANSWER ✔ It has two hot wires.
,11. In the absence of a cooling tower water treatment program
how often should the tower be flushed or the water replaced? -
ANSWER ✔ The water should be drained regularly each week
one or two times a week and replaced with fresh clean water.
12. What could occur if you fail to close the condenser water? -
ANSWER ✔ High condenser pressure could occur.
13. What does the muffler do in a refrigeration system? -
ANSWER ✔ It reduces noise, pulsations or vibrations.
14. Where is the muffler located? - ANSWER ✔ On the
discharge line.
15. What type of machine is a centrifugal compressor? -
ANSWER ✔ It is a high-volume low-pressure Machine.
16. How many pounds above the suction pressure is the
compressors oil pressure control, cut in point? - ANSWER ✔ 15-
30 pounds.
17. What is a transformer most commonly used for in a
refrigeration system? - ANSWER ✔ To step down voltage from
120 V to 24 V.
, 18. What form of heat is removed in the condenser? - ANSWER
✔ Both sensible and latent heat.
19. What do semi hermetic compressor's use to cool the motor? -
ANSWER ✔ They use the suction vapor of the machine.
20. Where is the water supply to the suction side of a lift pump
located? - ANSWER ✔ The water supply to the pump suction is
located below the pump level.
21. What does a thermostatic expansion valve maintain? -
ANSWER ✔ The thermostatic Expansion valve maintains a
constant evaporator superheat.
22. Is 55° chill water supply acceptable temperature for comfort
cooling? - ANSWER ✔ No, 55° chill water supply is too high for
comfort cooling. Optimal temperatures according to most chiller
designs is 45 F supply and 55 F return.
23. What does the drip on the pump packing gland indicate? -
ANSWER ✔ The drip shows that there is water in the pump.
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