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Commercial Refrigeration Certification Questions with 100% correct answers
Commercial Refrigeration Certification Questions with 100% correct answers
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Commercial Refrigeration CertificationIn 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. - -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. - -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 - -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.
B. evaporator outlet.
✅✅
C. condenser outlet.
D. receiver Inlet. - -A. compressor inlet. (Suction Line)
Superheat measurements are best taken:
A. during a hot pull down.
B. at 8°F to 12°F.
✅✅-D. with the system
C. during defrost.
D. with the system operating at design conditions. -
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. - -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. - -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 - -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
B. undercharge of refrigerant
✅✅
C. the circulator
D. the TEV - -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. - -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. - -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 - -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. - ✅✅-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.
✅✅
C. receivers.
D. accumulators. - -A. water cooled condensers.
The refrigerant condensing temperature in a water cooled condenser is normally
about ____ higher than the leaving water.
A. 100°F
B. 10°F
✅✅
C. 30°F
D. 75°F - -B. 10°F
The refrigerant in an air cooled condenser will normally condense at approximately
_____ higher temperature than the air passing over it.
A. 10°F
B. 30°F
✅✅
C. 75°F
D. 100°F - -B. 30°F
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 - -D. fan-cycle control
Cooling towers that pass air over water to remove system heat are limited in capacity
by:
A. outside air wet bulb temperature.
B. outside air dry bulb temperature
✅✅
C. inside air wet bulb temperature.
D. inside air dry bulb temperature. - -A. outside air wet bulb temperature.
One of the main reasons that reciprocating compressors are not 100% efficient is:
A. CFC refrigerants.
B. clearance volume.
✅✅
C. evaporator design
D. condenser design. - -B. clearance volume.
An open drive compressor is most likely to develop a refrigerant leak at the:
A. valve plate.
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