WATER HEATER

PROBLEM TO BE SOLVED: To provide a water heater which promptly supplies hot water all the time, maintains a hot water storage tank in a state of thermal stratification and reduces heat release loss. SOLUTION: A circulation pipe line 2 extended from a hot water supply side of a boiler 1 to a water replenishing side of the boiler 1 is provided, and a hot-water tap 5 is provided in the middle of the circulation pipe line 2. The hot water supply tank 7 is provided by the boiler 1, and the upper region is connected to the upstream side of the circulation pipe line 2 via an upper pipe 9. A three-way valve 15 is provided. In the three-way valve 15, a first inlet port is connected to the hot water supply side of the boiler 1, a second inlet port is connected to a lower pipe 10 led from the lower region of the hot water storage tank 7, and an outlet port is connected to the downstream side of the circulation pipe line 2. A thermostat detecting the temperature of the hot water supply side of the boiler 1 is provided. When the temperature is lower than a predetermined value, a flow rate to the first inlet port of the three-way valve 15 is increased and in contrast, when the temperature is higher than the predetermined value, a flow rate to the second port is increased, to control and maintain the hot water supply temperature of the boiler 1 at an approximately constant level. COPYRIGHT: (C)2011,JPO&INPIT