REFRIGERATED MERCHANDISER

A refrigerated merchandiser including a case, a refrigeration system, a sensor, and a controller. The refrigeration system is operable in a defrost mode defrosting the evaporator, and a refrigeration mode discharging a refrigerated airflow into the product storage area to refrigerate the product and to maintain the product within a predetermined temperature range without freezing the product, and to receive the refrigerated airflow along a return passageway. The sensor senses one or more defrost conditions of the case. The controller controls the refrigeration system in the refrigeration mode and in the defrost mode, and includes an algorithm for calculating when to initiate the defrost mode and for calculating a duration of the defrost mode. The controller is programmed to vary the refrigeration system between the refrigeration mode and the defrost mode based on the signals indicative of the defrost conditions and the calculations by the algorithm.