Commercial refrigeration Exam Latest
Updated Solved 100% Correct
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
Which type of system reduces total amount of refrigerant charge required? - Answer-
Secondary loop
The components for a self contained system - Answer- Are selected and assembled by
the equipment manufacturer
The normal fluid temperature drop through a glycol coil on a secondary cooling loop is -
Answer- 10 degrees
Compare the installation cost of multiple cases with a separate condensing unit for each
refrigerated case versus a rack system - Answer- The rack system generally will have a
lower installed cost
What is an uneven rack system? - Answer- A rack that has different capacity
compressors
Defrost on a low temperature case is normally accomplished - Answer- By shutting off
the compressor and energizing electric defrost heaters
If the evaporator in a reach in freezer is coated with a large quantity of ice - Answer- It
operates less efficiently because the ice acts as an insulation
Along with the refrigerant that is being discharged, reciprocating and rotary
compressors will discharge which of the following as it leaves the compressor? -
Answer- Oil
Updated Solved 100% Correct
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
Which type of system reduces total amount of refrigerant charge required? - Answer-
Secondary loop
The components for a self contained system - Answer- Are selected and assembled by
the equipment manufacturer
The normal fluid temperature drop through a glycol coil on a secondary cooling loop is -
Answer- 10 degrees
Compare the installation cost of multiple cases with a separate condensing unit for each
refrigerated case versus a rack system - Answer- The rack system generally will have a
lower installed cost
What is an uneven rack system? - Answer- A rack that has different capacity
compressors
Defrost on a low temperature case is normally accomplished - Answer- By shutting off
the compressor and energizing electric defrost heaters
If the evaporator in a reach in freezer is coated with a large quantity of ice - Answer- It
operates less efficiently because the ice acts as an insulation
Along with the refrigerant that is being discharged, reciprocating and rotary
compressors will discharge which of the following as it leaves the compressor? -
Answer- Oil
