Patent ID: 7716936

Claim:
A method for affecting a scheduled defrost operation for a refrigeration system; said scheduled defrost operation being initiated at a scheduled defrost commencement time by a defrost time clock in said refrigeration system; the method comprising the steps of: (a) adding a discrete defrost control unit coupled with said defrost time clock; (b) before said scheduled defrost commencement time, operating said discrete defrost control unit to effect evaluating at least one predetermined parameter relating to past operation of said refrigeration system; (c) if said at least one predetermined parameter manifests a behavior of at least one first predetermined nature over at least one first time interval, operating said discrete defrost control unit to permit said scheduled defrost operation; and (d) if said at least one predetermined parameter manifests a behavior of at least one second predetermined nature over at least one second time interval, operating said discrete defrost control unit to preempt commencement of said scheduled defrost operation.