What will cause Xiaomi Water Ionic Hair Dryer H500 to become hot and red inside?

There are two situations that can cause the heating wire to be red:
1Non-normal use, such as towels, clothes blocking the air outlet or the hair dryer is stuffed into the inside of the shoe, as well as other forms of blocking the hair dryer. Fan, this situation need to cut off the power supply and wait for a few minutes to ensure that the air inlet and outlet without blocking the use of the boot, such as the same If still appear, apply for after-sales service;
2, the hair dryer itself fails, apply for after-sales service.