Abstract: A sensing device for use in a control for an alarm indicating an undesirable operating temperature condition within a refrigeration apparatus cabinet. The sensing device is mounted to have at least one surface thereof in thermal association with a liner portion of the refrigeration apparatus cabinet defining a refrigeration chamber therein. The sensing device is further responsive to the temperature of the refrigerated air within the chamber. The sensing device incorporates a time delay in responding to temperature changes within the refrigerated chamber to avoid false operation of the alarm. The device may be mounted in an insulating housing to provide a further time delay in the air temperature sensing functioning thereof.