1. A method of programming the electronic processor control board of a refrigeration unit at the final assembly of the unit which comprises: determining the physical characteristics of the refrigeration unit; arranging a configuration header having a plurality of conducting wires therethrough on the processor control board; assigning each of said plurality of conducting wires to a preselected input of a microprocessor; electrically connecting the assigned conducting wire to an input of a microprocessor; and selectively developing a binary code for each input of the microprocessor by allowing or not allowing a signal through each conducting wire to be impressed on the input of the microprocessor to program the microprocessor to the determined physical characteristics of the refrigeration unit.