Refrigeration Final Exam Questions
With Complete Solutions
/. What is the normal box temp on a medium temp walk in refrigerator - Answer-35 to 37
degrees
/.What is the temp for reach ins - Answer-38 to 40 degrees
/.What is the temp on walk in Freezers - Answer--10 degrees
/.What is the temp on a reach in Freezer - Answer-0 degrees
/.What is the normal evaporator TD for a Reach in refrigerator or freezer - Answer-20
degrees. (40 box - 20 evap =20)
/.What is the normal evap TD for a walk in refrigerator or Freezer - Answer-20 degrees
(35 box - 25 evap = 10)
/.How is evaporator temperature or TD calculated - Answer-Using the difference
between the evaporator temp and the temp of the box.
/.How do you get the Evaporator Temp? - Answer-Use the suction pressure and convert
Pressure to Temp on a P/T chart
/.What is condenser split - Answer-The difference between the Ambient temp and the
Condensers temp.
/.What is the CS for refrigerators - Answer-Most are 30 degrees CS at 95 ambient
/.What is the CS for Freezers - Answer-20 to 25 degrees CS
/.What is normal superheat on a refrigerator - Answer-10 degrees
/.What is normal superheat on a freezer - Answer-5 degrees
/.What is normal Subcooling for refrigeration - Answer-10 degrees
/.What is normal Subcooling on high seer(efficiency) - Answer-15-20 degrees
/.What does a 5 degrees or below of Subcooling usually indicate - Answer-
Undercharged
, /.What does 20 degrees of above of Subcooling usually indicate - Answer-Overcharged
/.What would a superheat of 0 degrees always indicate - Answer-Flooding back to the
compressor
/.What does a superheat of 5 degrees or below indicate - Answer-Flooding
/.What does a superheat of 20 degrees or above indicate - Answer-Starving
/.What does a superheat of 10 degrees indicate - Answer-Usually properly charged.
/.If a refrigerator box has a temp of 35 what would you expect the evaporator temp to be
- Answer-25 degrees (based on a 10 degree TD)
/.If the ambient temp is 90 degrees what would you expect the Liquid line temp to be? -
Answer-60 degrees (based on a 30 degree CS)
/.Will an ambient of 70 degree give a lower CS than 95 degree ambient? - Answer-Yes
/.Why would a low ambient give a lower CS - Answer-Lower load more efficient
/.What is the relationship of Evap TD to box humidity - Answer-The low the Evap TD the
Higher the humidity
/.How does an evaporator Load affect Evap Temps and pressures - Answer-High loads
mean too much heat to absorb, both temp and pressure are high
/.What does a high evaporator load do to Superheat - Answer-It would be high
/.How does ambient temp affect the condensing temp and pressures - Answer-Lower
pressure and temp
/.How does a dirty condenser affect condensing temps, pressures - Answer-Higher
pressure and temps (prevents rejection of heat)
/.How does dirty or iced evaporator affect evap temps, pressure - Answer-Heat won't be
absorbed so less temp, less pressure
/.How do fixed metering devices react to what is going on in condensers or evaporator, -
Answer-They are designed to feed a fixed amount so they don't really change.
/.How does a TEV act to what is going on in the condensers and evaporator? - Answer-
They try to maintain a constant superheat in the evaporator so can feed more or less.
/.The air entering a walk in refrigerator air cooled condenser is 90 degrees, what should
the condensing temp be? - Answer-120 degrees (refrigerator CS 30)
With Complete Solutions
/. What is the normal box temp on a medium temp walk in refrigerator - Answer-35 to 37
degrees
/.What is the temp for reach ins - Answer-38 to 40 degrees
/.What is the temp on walk in Freezers - Answer--10 degrees
/.What is the temp on a reach in Freezer - Answer-0 degrees
/.What is the normal evaporator TD for a Reach in refrigerator or freezer - Answer-20
degrees. (40 box - 20 evap =20)
/.What is the normal evap TD for a walk in refrigerator or Freezer - Answer-20 degrees
(35 box - 25 evap = 10)
/.How is evaporator temperature or TD calculated - Answer-Using the difference
between the evaporator temp and the temp of the box.
/.How do you get the Evaporator Temp? - Answer-Use the suction pressure and convert
Pressure to Temp on a P/T chart
/.What is condenser split - Answer-The difference between the Ambient temp and the
Condensers temp.
/.What is the CS for refrigerators - Answer-Most are 30 degrees CS at 95 ambient
/.What is the CS for Freezers - Answer-20 to 25 degrees CS
/.What is normal superheat on a refrigerator - Answer-10 degrees
/.What is normal superheat on a freezer - Answer-5 degrees
/.What is normal Subcooling for refrigeration - Answer-10 degrees
/.What is normal Subcooling on high seer(efficiency) - Answer-15-20 degrees
/.What does a 5 degrees or below of Subcooling usually indicate - Answer-
Undercharged
, /.What does 20 degrees of above of Subcooling usually indicate - Answer-Overcharged
/.What would a superheat of 0 degrees always indicate - Answer-Flooding back to the
compressor
/.What does a superheat of 5 degrees or below indicate - Answer-Flooding
/.What does a superheat of 20 degrees or above indicate - Answer-Starving
/.What does a superheat of 10 degrees indicate - Answer-Usually properly charged.
/.If a refrigerator box has a temp of 35 what would you expect the evaporator temp to be
- Answer-25 degrees (based on a 10 degree TD)
/.If the ambient temp is 90 degrees what would you expect the Liquid line temp to be? -
Answer-60 degrees (based on a 30 degree CS)
/.Will an ambient of 70 degree give a lower CS than 95 degree ambient? - Answer-Yes
/.Why would a low ambient give a lower CS - Answer-Lower load more efficient
/.What is the relationship of Evap TD to box humidity - Answer-The low the Evap TD the
Higher the humidity
/.How does an evaporator Load affect Evap Temps and pressures - Answer-High loads
mean too much heat to absorb, both temp and pressure are high
/.What does a high evaporator load do to Superheat - Answer-It would be high
/.How does ambient temp affect the condensing temp and pressures - Answer-Lower
pressure and temp
/.How does a dirty condenser affect condensing temps, pressures - Answer-Higher
pressure and temps (prevents rejection of heat)
/.How does dirty or iced evaporator affect evap temps, pressure - Answer-Heat won't be
absorbed so less temp, less pressure
/.How do fixed metering devices react to what is going on in condensers or evaporator, -
Answer-They are designed to feed a fixed amount so they don't really change.
/.How does a TEV act to what is going on in the condensers and evaporator? - Answer-
They try to maintain a constant superheat in the evaporator so can feed more or less.
/.The air entering a walk in refrigerator air cooled condenser is 90 degrees, what should
the condensing temp be? - Answer-120 degrees (refrigerator CS 30)
