Refrigeration test Exam Questions with
Complete Solutions
What is considered a normal box temperature of a walk-in refrigerator - Answer-35-38F
What is considered a normal box temperature for a reach in refrigerator - Answer-38-
40F
What is considered a normal box temperature of a walk-in freezer - Answer--10F
What is considered a normal box temperature for a reach in freezer - Answer-0 degrees
Fahrenheit
How can latent heat in a suction line be transferred to a higher outdoor temperature -
Answer-Compress the suction vapor until its condensing temperature is higher than the
ambient.
Why do zeotropic blends have temperature glide - Answer-do not have a common
boiling point for all the constituents.
Under what circumstances should a technician use TROT - Answer-When factory
information is not available.
If the condensing temperature is 125F and the evaporator temperature is 25F what
refrigerants are being used - Answer-R404A?
What is considered to be evaporator temperature - Answer-The temperature of the
refrigerant inside the evaporator tubing.
How do you calculate evaporate temperature from the suction pressure - Answer-Use a
PT chart
How is evaporator temperature difference calculated for a walk-in cooler - Answer-
Subtract the SST from the box temperature.
What is a hot pull down - Answer-a condition in which the refrigerator has difficulty
removing heat from the box.
During hot pull down what is the evaporator experiencing - Answer-the evaporator coil
starves
As TD increases how does it affect box humidity - Answer-It decreases
, If airflow across the evaporator decreases what effect does it have on the evaporator
temperature and suction pressure - Answer-both decrease.
Why are multiple circuits used on a large evaporator coil - Answer-They provide less
pressure drop than a long single circuit evaporator.
How do you determine the evaporator superheat of a refrigeration system - Answer-
Subtract evaporator temperature from the temperature of the suction line at the
expansion valve bulb.
A 10F walk in freezer using r404A has a suction pressure of 15 psig. The suction line
temperature at the txv bulb is -20F what is the evaporator superheat. - Answer-The
evaporator superheat in the given scenario is 10ºF
A superheat below 5F indicates the evaporator is experiencing which of the following -
Answer-over charged with refrigerant by the metering device
How many degrees of box temp can you check superheat - Answer-5 degrees
Why is it necessary for the fin spacing in a freezer evap to be wide - Answer-Frost
buildup will not occur as fast if the fin spacing is wide
WHat is the basic sequence of operation at the beginning of a freezer defrost - Answer-
Evaporator fans shut off, compressor shuts off, and heaters come on.
What is the primary function of the condenser? - Answer-to transfer heat from the
refrigerant to another medium, such as air and/or water.
Why does the suction vapor have to be increased in temp before it can be condensed -
Answer-the extra heat provides the molecules with more energy, allowing for a higher
pressure that enables the vapor to condify when cooled
How can the temp of refrigerant be increased without any excess of heat - Answer-By
increasing the pressure
What are the 3 phases of the condenser - Answer-desuperheating, condensation and
sub-cooling.
Where does the SH in discharge gas come from - Answer-Suction vapor heat,
compressor motor heat, and heat of compression
Where does the SH in added heat come from - Answer-any temperature of the vapor
above the saturation temperature
What happens inside the compressor - Answer-Converts gas
Complete Solutions
What is considered a normal box temperature of a walk-in refrigerator - Answer-35-38F
What is considered a normal box temperature for a reach in refrigerator - Answer-38-
40F
What is considered a normal box temperature of a walk-in freezer - Answer--10F
What is considered a normal box temperature for a reach in freezer - Answer-0 degrees
Fahrenheit
How can latent heat in a suction line be transferred to a higher outdoor temperature -
Answer-Compress the suction vapor until its condensing temperature is higher than the
ambient.
Why do zeotropic blends have temperature glide - Answer-do not have a common
boiling point for all the constituents.
Under what circumstances should a technician use TROT - Answer-When factory
information is not available.
If the condensing temperature is 125F and the evaporator temperature is 25F what
refrigerants are being used - Answer-R404A?
What is considered to be evaporator temperature - Answer-The temperature of the
refrigerant inside the evaporator tubing.
How do you calculate evaporate temperature from the suction pressure - Answer-Use a
PT chart
How is evaporator temperature difference calculated for a walk-in cooler - Answer-
Subtract the SST from the box temperature.
What is a hot pull down - Answer-a condition in which the refrigerator has difficulty
removing heat from the box.
During hot pull down what is the evaporator experiencing - Answer-the evaporator coil
starves
As TD increases how does it affect box humidity - Answer-It decreases
, If airflow across the evaporator decreases what effect does it have on the evaporator
temperature and suction pressure - Answer-both decrease.
Why are multiple circuits used on a large evaporator coil - Answer-They provide less
pressure drop than a long single circuit evaporator.
How do you determine the evaporator superheat of a refrigeration system - Answer-
Subtract evaporator temperature from the temperature of the suction line at the
expansion valve bulb.
A 10F walk in freezer using r404A has a suction pressure of 15 psig. The suction line
temperature at the txv bulb is -20F what is the evaporator superheat. - Answer-The
evaporator superheat in the given scenario is 10ºF
A superheat below 5F indicates the evaporator is experiencing which of the following -
Answer-over charged with refrigerant by the metering device
How many degrees of box temp can you check superheat - Answer-5 degrees
Why is it necessary for the fin spacing in a freezer evap to be wide - Answer-Frost
buildup will not occur as fast if the fin spacing is wide
WHat is the basic sequence of operation at the beginning of a freezer defrost - Answer-
Evaporator fans shut off, compressor shuts off, and heaters come on.
What is the primary function of the condenser? - Answer-to transfer heat from the
refrigerant to another medium, such as air and/or water.
Why does the suction vapor have to be increased in temp before it can be condensed -
Answer-the extra heat provides the molecules with more energy, allowing for a higher
pressure that enables the vapor to condify when cooled
How can the temp of refrigerant be increased without any excess of heat - Answer-By
increasing the pressure
What are the 3 phases of the condenser - Answer-desuperheating, condensation and
sub-cooling.
Where does the SH in discharge gas come from - Answer-Suction vapor heat,
compressor motor heat, and heat of compression
Where does the SH in added heat come from - Answer-any temperature of the vapor
above the saturation temperature
What happens inside the compressor - Answer-Converts gas
