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Refrigeration Excellence Exam Questions and Answers
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Refrigeration Excellence1. In a dry type (direct expansion) evaporator, liquid refrigerant must boil away as close
to the end of the coil as possible in order to:
A. Operate at high-efficiency
B. Ensure that Frost is not accumulate
C. Subcool the compressor
D. Ensure proper oil return - Question and answersA. Operate at high-efficiency
2. The difference between the temperature of the refrigerant boiling in the evaporator
and the temperature at the evaporator outlet is known as
A. Evaporator superheat
B. Latent heat
C. Evaporator sub-cooling
D. Sublimation - Question and answersA. Evaporator superheat
3. An expansion device that is stuck open will cause
A. Low suction pressure
B. A starved evaporator
C. Excessive superheat
D. A flooded evaporator - Question and answersD. A flooded evaporator
4. When measuring evaporator superheat on a commercial system that has a long
suction line, the pressure reading should be taken at the
A. Compressor inlet
B. Evaporator outlet
C. Condenser outlet
D. Receiver Inlet - Question and answersA. Compressor inlet
5. Superheat measurements are best taken
A. During a hot pulldown
B. At 8°F two 12°F
C. During defrost
D. With the system operating at design conditions - Question and answersD. With the
system operating at design conditions
6. A technician is checking the superheat on a multi circuit evaporator and finds one of
the circuits has a superheat that is higher than the others. This could be caused by
A. A dirty coil
B. A refrigerant overcharge
C. Uneven air distribution
,D. A blocked distributor - Question and answersD. A blocked distributor
7. A TXV with an external equalizer is used on
A. Evaporators with a high pressure drop
B. Evaporators with a low pressure drop
C. High temperature application is only
D. All evaporators - Question and answersA. Evaporators with a high pressure drop
8. Dry type evaporators operate most efficiently with the superheat setting of
approximately
A. 8°F to 12°F
B. 13°F to 19°F
C. 20°F to 30°F
D. 31°F to 40°F - Question and answersA. 8°F to 12°F
9. An evaporator used to chill liquids is operating within normal superheat setting. But
the system is not cooling the product properly. Which of the following is most likely the
cause?
A. Overcharge of refrigerant
B. Undercharge of refrigerant
C. The circulator
D. The TXV - Question and answersA. Overcharge of refrigerant
10. What time interval is required between each superheat adjustment?
A. Not less than one hour
B. About 10 to 15 minutes
C. At least a half hour
D. No time delay - Question and answersB. About 10 to 15 minutes
11. A low temperature evaporator used for cooling space or product refrigeration
A. Is the same as one used for medium or high temperatures
B. Must have fins space closer together
C. Must be frosted periodically
D. Must be defrosted periodically - Question and answersD. Must be defrosted
periodically
12. Some special applications use a flooded evaporator (operated full of refrigerant) in
order to maintain the proper level of liquid refrigerant, a ______ type devices used.
A. High side float
B. Capillary tube
C. AEV
D. Low side float - Question and answersD. Low side float
13. A properly functioning condenser will first
A. Condense, then de-superheat
B. Sub-cool, then de-superheat
, C. Sub-cool, then superheat
D. De-superheat, then sub-cool - Question and answersD. De-superheat, then sub-cool
14. The effect of an inefficient water cooled condenser will
A. Act the same as an air cooled condenser
B. Act different than an air cooled condenser
C. Always be mixed with incoming medium without being reheated
D. Seldom be inefficient on commercial equipment - Question and answersA. Act the
same as an air cooled condenser
15. The refrigerant condensing temperature in a water cooled condenser is normally
about _____ higher than the leaving water.
A. 5°F
B. 10°F
C. 15°F
D. 20°F - Question and answersB. 10°F
16. The refrigerant and an air cooled condenser will normally contends at approximately
_____ higher temperature than the air passing over it.
A. 10°F
B. 30°F
C. 75°F
D. 100°F - Question and answersB. 30°F
17. Workable head pressure during periods of low ambient temperature can be
achieved by using
A. An economizer
B. Evaporator dampers
C. Evaporator flooding
D. Fan cycle control - Question and answersD. Fan cycle control
18. Cooling towers that pass air over water to remove system heat are limited in
capacity by
A. Outside air wetbulb temperature
B. Outside air dry bulb temperature
C. Inside air wetbulb temperature
D. Inside air dry bulb temperature - Question and answersA. Outside air wetbulb
temperature
19. Parallel compressors often referred to as a rack system may use
A. A common suction, but not a common discharge header
B. A common discharge header, but not a comment section header
C. Both comment section header and common discharge header
D. A common accumulator, but never a common receiver - Question and answersA. A
common suction, but not a common discharge header
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