INSTANTANEOUS WATER HEATER

PURPOSE:To stabilize the hot-water temperature and shorten the heating time by a method wherein a hot-water temperature detecting part is provided at the outlet side of a heat exchanger, a water quantity control valve is provided, said control valve is made to be operated toward the opening (closing) direction when the detected temperature is higher (lower) than the preset temperature, also an orifice the water quantity required for igniting level is flowed therethrough is provided in parallel with the water control valve. CONSTITUTION:At the opening of a tap 10, a valve 20 is closed caused by the ordinary temperature of a hot-water temperature detector 12, water is made to be flowed through only an orifice 14, the water flow quantity is made to be the igniting water quantity level. Meanwhile, a water quantity detector 2 is operated, a water pressure reaction valve 5 is opened, a burner 6 is ignited. With the heating, the valve 20 of a water quantity control part 13 is gradually opened, the water quantity is also gradually increased. The opening degree of the valve 20 is adjusted for supplying the designated hot-water temperature. At the moment just after ignition, the water flow quantity is small as only required for the igniting water quantity level, accordingly, the energy loss from the tap is less, the heating time can be shortened.