PURPOSE: To supply hot-water having proper temperature during operation and at the initial time of operation and facilitate piping by a method wherein one end of a water introducing pipe is extended to the main body of a hot-water reserving tank through heat insulating material and one end of a hot-water supplying pipe is extended to the same through reserved water while these pipes are connected to a hot-water supplying pump through a mixing cock.

CONSTITUTION: One end of a water introducing pipe 30 is extended to the bottom of a hot-water reserving tank main body 10 through heat insulating material 10c and one end of a hot-water supplying pipe 40 is extended to the lower side of the tank main body 10 through reserved water while these pipes are connected to a hot-water supplying pump 60 through a mixing cock 50. Accordingly, the water introducing pipe 30 is insulated by the heat insulating material 10c and the pipe will never deprive heat from the reserved water in the tank, therefore, the hot-water reserving efficiency of the tank main body can be improved. On the other hand, the hot-water supplying pipe 40 is heated by the reserved water and the water introducing pipe 30 is insulated by the heat insulating material, therefore, water, having predetermined temperatures is supplied to the mixing cock 50 from the very initial time of operation and hot-water, having proper temperature, may be delivered. Further, water, which flows into said mixing cock, is introduced through the water introducing pipe, therefore, piping work may be facilitated.