Common fault points are: 1. The auxiliary water tank boiling may be caused by the damage of the auxiliary kettle cover. 2. The auxiliary water tank may boil due to damage to the thermostat in the cooling system. 3. The auxiliary water tank boiling may be caused by the cooling fan in the cooling system not working properly. The above three points are common fault points. For specific faults, it is recommended to check them as soon as possible.