Abstract: Gas water heater is also called gas water heater. its main function is to prepare domestic hot water. with the popularity of gas water heater, users are demanding higher and higher energy saving and timeliness of hot water. How to quickly and efficiently prepare domestic hot water has become the focus of research and development by major manufacturers. This paper introduces an implementation scheme of a gas water heater that can quickly produce hot water, designs the functional diagram of the hardware system, and gives the program flow chart for realizing fast hot water.

Key words: Fast hot water, Self-study, Gas water heater