The HD680 gas water heater pays attention to a family’s water experience and their safety. It is equipped with an intelligent temperature-monitoring system that can automatically adjust the temperature to what is comfortable for the human body according to seasonal changes. The equipment has a dynamic circulation preheating system that allows users to enjoy the experience of continuous hot water. It is also suitable for the elderly and babies with an exclusive temperature mode for them that can be switched on with one click. The HD680 is equipped with 13 safety protection measures to ensure the water safety of users.