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
The advantage of ball valves over other types of manual refrigeration valve is that they? -
ANSWER - Offer less resistance to flow
In most commercial refrigeration systems, most of the excess refrigerant that is not being used
is stored in? - ANSWER - The liquid receiver
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
The advantage of ball valves over other types of manual refrigeration valve is that they? -
ANSWER - Offer less resistance to flow
In most commercial refrigeration systems, most of the excess refrigerant that is not being used
is stored in? - ANSWER - The liquid receiver
