A refrigeration system control apparatus for use with an ice bank (10) for sequentially cycling a refrigerator compressor (16) on and off based on sensed conditions. The system includes a first temperatures probe (120) located a first distance from a refrigerator evaporator coil (14) and a second temperature probe (122) located a second, greater distance from the refrigerator evaporator coil (14). A programmable controller (130) monitors temperature outputs from the first and second temperature probes (120, 122) and turns on and off the refrigerator compressor (16) based upon a rate of change of the temperature difference between the sensed temperatures of the first and second probes (120, 122).