Commercial Refrigeration Exam
Questions and Answers (Graded
A)
The defrost cycle is normally terminated - ANSWER - Based on either temperature,
pressure, or time
Why would a 35 degree meduim temperature case need to defrost? - ANSWER - The
coil temperature for a 35 degree box opertes below freezing
The lowest evaporator coil temperature that traditional mechanical systems can
attain is approximately - ANSWER - -40 degrees
A system that maintains temperatures of -250 degrees and below is a - ANSWER -
Cryogenic system
Three common methods of controlling evaporator temperature are - ANSWER -
Conventional thermostat, a suction pressure cut out control, or an evaporator
pressure regulator
When a reach in cooler or freezer is not located near a drain evaporator condensate
is - ANSWER - Drained into a heated pan that evaporates the water
Why is a check valve installed in the auction line of the lowest temperature coil in
multiple evaporator system? - ANSWER - To prevent refrigerant migration from the
higher temperature and pressure coil to the lower temperature and pressure coil
What is commonly used to control defrost operations? - ANSWER - Defrost timer
When multiple compressors are installed in parallel on the same refrigeration
system, provisions must be made to ensure that - ANSWER - The oil level is correct
in all compressors
, What are the broad areas that commercial refrigeration equipment is grouped in
based on the evaporator coil temperature? - ANSWER - High, medium, low, and
cryogenic temperatures
What is the purpose of the door switch on a walk in freezer? - ANSWER - To prevent
warm air from entering the case by shutting off the fans when the door is opened
What is the approximate ventilation requirement for low temperatures, air cooled
condensing units located indoors? - ANSWER - 200 cfm per 1000 btu
A refrigerated case that maintains a temperature of 28 degrees would be classified
as - ANSWER - A medium temperature system
Why should the evaporator not be installed above the door in a walk in cooler or
freezer? - ANSWER - It will draw warm humid air and frost more quickly
What is that normal storage temperature for food items like milk, cheese, fresh
fruits and vegetables? - ANSWER - From 32 degrees to 40 degrees
The first step in selecting commercial refrigeration equipment for a new installation
is to - ANSWER - Perform a heat load calculation to determine the required btu
capacity of the system
What refrigeration component makes it possible to use a single compressor to
control multiple cases at different temperatures? - ANSWER - Evaporator pressure
regulator
What is the advantage of using multiple compressors on a supermarket rack
system? - ANSWER - System capacity can match refrigeration loads that vary over a
wide range
What must be considered when performing a heat load calculation for a walk in
cooler or freezer are - ANSWER - Heat transmission, air infiltration, and product load
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