Only the mechanical thermostat of the old refrigerator is on the side or top of the refrigerating room, and the digital gear size should be adjusted according to the seasonal environmental temperature. Usually the thermostat has 1-7 gear. The ambient temperature is very high in summer, so it should be set and adjusted at a smaller mathematical coaxial position (1-3), and it can be adjusted in the middle gear in spring and autumn (3-4). In winter, the indoor temperature is very low, so it is necessary to adjust to a larger mathematical gear (5-6). It's best to put a thermometer in the refrigerator to measure. If the temperature is high, raise the math gear, if the temperature is low, lower the gear.