What is the cause of the abnormal temperature of the κλίβανος αντίστασης τύπου κουτιού υψηλής θερμοκρασίας

①The thermocouple is not inserted into the furnace, causing the furnace temperature to run out of control.

②The index number of the thermocouple is inconsistent with the index number of the temperature control instrument, which will cause the furnace temperature to be inconsistent with the temperature displayed by the temperature control instrument.