Abstract: Through analyzing the causes and hazards of water hammer produced by traditional old heater,this paper describes the working principles,structure and engineering application of the first generation water-hammerless energy-saving heater as well as the existing problems and shortcomings during its application.Meanwhile,it expatiates on the unique advantages of the new all butt joints water-hammerless energy-efficient tank heater.Theoretical analysis and practical application show that：compared with traditional heater,the water-hammerless tank heater eliminates the water hammer phenomenon in operation,featuring better heating effect,higher heating speed,less steam consumption,and more obvious energy-saving effect;and the new all butt joints waterhammerless energy-efficient tank heater solves the bottleneck problem of production quality which exists in the first generation water-hammerless heater,being more durable and widely used.Therefore,the new all butt joints water-hammerless heater represents the development direction of tank heating facilities.