Answer:
The evaporator fan(vertical freezer)
1.When the compartment temperature is high, the freezer runs, the evaporator fan runs, when the compartment temperature is lower enough, the freezer stops , the evaporator fan stops too.
2.If you open the door, the fan stops.
The cooling fan
1.When the compartment temperature is high, the freezer runs, the cooling fan runs, when the compartment temperature is lower enough, the freezer stops , the cooling fan stops too.
Notice:
1.Some of the vertical freezer, if the upper and lower temperature of the compartment if high enough, the evaporator fan will run to keep the temperature uniformity.
2. When the ambient temperature is high , the freezer will run for a longer time and the fans will run for a longer time.