This 60Hz 120V defrost timer will cycle for thirty minutes after every eight hours of run time. You can turn the dial on the defrost timer clockwise to be able to advance it in and out of defrost mode. The defrost timer helps melt away any ice that may have built up on the evaporator coils. If your refrigerator/freezer is too warm or too cold, will not advance into the defrost cycle, freezer will not defrost, or it runs too long, the defrost timer may be defective and will need to be replaced. This is a genuine OEM part. Please remember to disconnect the power to the refrigerator before starting your repair.