TEMPERATURE CONTROL SYSTEM FOR REFRIGERATOR/FREEZER COMBINATIONS

摘要

A combined refrigerator/freezer unit provides a step motor driven damper for adjusting the relationship between the amount of chilled air delivered to the freezer compartment and the amount of chilled air delivered to the refrigeration department. The step motor, and in turn, the damper, is controlled by an integrated circuit which receives signals from temperature sensors in each compartment. The control produces pulses which cause the step motor to readjust the position of the damper to correct temperature imbalances which exist within the two compartments. The step motor functions to move the damper to predetermined adjusted positions without requiring any feedback to establish the actual position of the damper before and after each adjustment. The control also functions during defrost to cause the evaporator temperature to be raised prior to the operation of the defrost heaters.