What should I do if the temperature of the box-type resistance furnace used is abnormal?

Abnormal temperature is one of the very common problems in the use of box-type resistance furnaces. In this case, the first thing to see is whether the thermocouple is correctly inserted into the furnace. When the thermocouple is correctly inserted, observe its index. Whether the number is consistent with the graduation number of the temperature control instrument, if these two problems are resolved, there will be basically no abnormal furnace temperature.