1, temperature sensor failure: the temperature sensor failed to measure the temperature correctly, resulting in a red light and a blue light unchanged. Check whether the temperature sensor works normally and replace it with a new one.

2. Damage of heat preservation function: The heat preservation function of the hot water kettle has been damaged, and the water temperature cannot be maintained, resulting in the red light turning blue all the time. Check whether the thermal insulation function of the hot water kettle is normal, and replace it with new thermal insulation functional parts.

3. Circuit failure: The circuit of the hot water kettle has failed, causing the red light to turn blue all the time. Check whether the circuit of the hot water kettle works normally, and ask professional maintenance personnel to check the maintenance circuit problems.