1. The power board of the liquid thermostat does not respond after being electrified, and the indicator light does not light up, indicating that the power supply is short-circuited or the line is faulty.

2. If you have the knowledge and skills of electronic maintenance, you can check whether the fuses, solder joints and electronic components on the power board are normal. If burnt parts or circuits are found to be damaged, you can try to replace the faulty parts or repair them by welding.