Commercial Refrigeration Certification
Exam Questions With 100% Verified
Answers.
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 does not accumulate.
C. sub-cool the compressor.
D. ensure proper oil return. - answer✔A. operate at high efficiency.
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. - answer✔A. evaporator superheat.
An expansion device that is stuck open will cause:
A. low suction pressure
B. a starved evaporator.
C. excessive superheat
D. a flooded evaporator - answer✔D. a flooded evaporator
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.
D. receiver Inlet. - answer✔A. compressor inlet. (Suction Line)
Superheat measurements are best taken:
A. during a hot pull down.
B. at 8°F to 12°F.
C. during defrost.
D. with the system operating at design conditions. - answer✔D. with the system operating at
design conditions.
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. - answer✔D. a blocked distributor.
A TEV with an external equalizer is used on:
A. evaporators with a high pressure drop.
B. evaporators with a low pressure drop.
C. high temperature applications only.
D. all evaporators. - answer✔A. evaporators with a high pressure drop.
Dry type evaporators operate most efficiently with a 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 - answer✔A. 8° F to 12°F
An evaporator used to chill liquids in operating with a normal superheat setting, but the system is
not cooling the product properly. Which of the following is the most likely cause?
A. overcharge of refrigerant
D. the TEV - answer✔C. the circulator
What time interval is required between each superheat adjustment?
A. Not less than 1 hour
B. About 10-15 minutes
C. At least 1/2 hour.
D. No time delay. - answer✔B. About 10-15 minutes
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 spaced closer together.
C. must be frosted periodically.
D. must be defrosted periodically. - answer✔D. must be defrosted periodically.
Some special applications use a flooded evaporator (operated full of refrigerant). In order to
maintain the proper level of liquid refrigerant, a ____ type metering device is used.
A. TEV
B. capillary tube
C. AEV
D. float - answer✔D. float
A properly functioning condenser will first:
A. condense then de-superheat.
B. subcool then de-superheat.
C. subcool then superheat.
D. de-superheat then subcool. - answer✔D. de-superheat then subcool.
Tube within a tube, shell and coil, and shell and tube are all types of:
A. water cooled condensers.
B. air cooled condensers.
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