There are generally several reasons for the thermistor to burn out:
1, the instantaneous current of the thermistor is too large, breakdown the resistance coil;
2, thermistor resistance wire insulation protection wear to form a short circuit between coils;
3, the line voltage is unstable, fluctuation is large, and the instantaneous voltage exceeds the safety index of the thermistor.
The above three points are only the causes of general problems, and the specific situation depends on your use environment and other factors.