Patent attributes
A water heater includes one or a plurality of heat pumps that heat tap water or return water from a hot water supply part, a circulation line that supplies hot water heated in the heat pumps to the hot water supply part, and introduces the return water from the hot water supply part to the heat pumps, an incoming water pipe that joins to between the hot water supply part in the circulation line and the heat pumps and supplies the tap water, a circulation pump that returns the return water to the heat pumps and circulates the return water through the circulation line, and a control unit that controls operation or stop of the circulation pump according to driving operation time or elapsed stop time by linking a combustion process of the heat pumps.