Commercial Refrigeration Ch 1 &
2 Questions and Answers 100%
Correct
What is considered the "normal" box temperature of a walk-in refrigerator? -
ANSWER - 35°F-37°F
What is considered the "normal" box temperature of a reach-in refrigerator? -
ANSWER - 38°F-40°F
What is considered the "normal" box temperature of a walk-in freezer? - ANSWER -
−10°F
What is considered the "normal" box temperature of a reach-in freezer? - ANSWER -
0°F
Why is the temperature of walk-ins usually lower than the temperature of reach-ins?
- ANSWER - Walk-ins are designed for long-term storage and lower temperatures.
How can the latent heat in a cold suction line be transferred to higher outdoor air
temperatures? - ANSWER - Compress the suction vapor until its condensing
temperature is higher than the ambient.
What is the primary difference between the AC system of Figure 1-1 and the
refrigeration system of Figure 1-2? - ANSWER - The refrigeration unit has to lower
the evaporator temperature.
Which refrigerant is used most in recently installed walk-in refrigerators? - ANSWER
- R404A
, Which refrigerant is used most in recently installed reach-in refrigerators? - ANSWER
- R134a and R404a
During Freezer Defrost, what is powered OFF? - ANSWER - Evaporator Fan,
thermostat, and solenoid coil
During Freezer Defrost, what is powered ON? - ANSWER - Defrost Heater & 1 side of
Defrost Termination Solenoid
One indication of a bad fan delay is... - ANSWER - icicles on the box ceiling and ice
on the fan blades because closed contacts would allow the fan to start as soon as
the unit is back in the freeze cycle.
Which refrigerant is used most in recently installed walk-in freezers and reach-in
freezers? - ANSWER - R404A
Why do zeotropic blends have temperature glide? - ANSWER - The component
refrigerants boil off at different rates.
Under what circumstances should a technician use TROT? - ANSWER - When the
factory information is not available.
Discharge Vapor Contains what 4 sources of Heat? - ANSWER - 1. Evap Superheat 2.
SuctionLine Superheat 3. Compressor motor heat 4. Heat of compression
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for AC - ANSWER - 35°F TD at 50
percent RH
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for Reach-In - ANSWER - 25°F TD at 65
percent RH
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for Walk-In - ANSWER - 10°F TD at 85
percent RH
2 Questions and Answers 100%
Correct
What is considered the "normal" box temperature of a walk-in refrigerator? -
ANSWER - 35°F-37°F
What is considered the "normal" box temperature of a reach-in refrigerator? -
ANSWER - 38°F-40°F
What is considered the "normal" box temperature of a walk-in freezer? - ANSWER -
−10°F
What is considered the "normal" box temperature of a reach-in freezer? - ANSWER -
0°F
Why is the temperature of walk-ins usually lower than the temperature of reach-ins?
- ANSWER - Walk-ins are designed for long-term storage and lower temperatures.
How can the latent heat in a cold suction line be transferred to higher outdoor air
temperatures? - ANSWER - Compress the suction vapor until its condensing
temperature is higher than the ambient.
What is the primary difference between the AC system of Figure 1-1 and the
refrigeration system of Figure 1-2? - ANSWER - The refrigeration unit has to lower
the evaporator temperature.
Which refrigerant is used most in recently installed walk-in refrigerators? - ANSWER
- R404A
, Which refrigerant is used most in recently installed reach-in refrigerators? - ANSWER
- R134a and R404a
During Freezer Defrost, what is powered OFF? - ANSWER - Evaporator Fan,
thermostat, and solenoid coil
During Freezer Defrost, what is powered ON? - ANSWER - Defrost Heater & 1 side of
Defrost Termination Solenoid
One indication of a bad fan delay is... - ANSWER - icicles on the box ceiling and ice
on the fan blades because closed contacts would allow the fan to start as soon as
the unit is back in the freeze cycle.
Which refrigerant is used most in recently installed walk-in freezers and reach-in
freezers? - ANSWER - R404A
Why do zeotropic blends have temperature glide? - ANSWER - The component
refrigerants boil off at different rates.
Under what circumstances should a technician use TROT? - ANSWER - When the
factory information is not available.
Discharge Vapor Contains what 4 sources of Heat? - ANSWER - 1. Evap Superheat 2.
SuctionLine Superheat 3. Compressor motor heat 4. Heat of compression
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for AC - ANSWER - 35°F TD at 50
percent RH
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for Reach-In - ANSWER - 25°F TD at 65
percent RH
T.R.O.T. FOR EVAPORATOR TD AND HUMIDITY for Walk-In - ANSWER - 10°F TD at 85
percent RH
