WATER HEATER

PROBLEM TO BE SOLVED: To attain miniaturization/lightweight/increase in efficiency, by using a single heat source for hot water supply, heating and bath, with a combination of a hot water supply heat exchanger and a latent heat recovery heat exchanger. SOLUTION: The water heater comprises the hot water supply heat exchanger 15 and the latent heat recovery heat exchanger 16. The heat exchanger 15 and the heat exchanger 16 are connected in series to form a hot water supply circuit extending from a water supply passage 1 to a hot water supply passage 3 through the heat exchanger 16 and then the heat exchanger 15, and also form a hot water circulation circuit 19 branched from the hot water supply passage 3 and including a circulating pump 17 and a check valve 27, which supplies hot water to a using-side heat exchanger 18, then returns it to the heat exchanger 16, and carries it to the using-side heat exchanger 18 again through the heat exchanger 15. Use of the hot water supply circuit, use of the hot water circulation circuit or simultaneous use of the hot water supply circuit and the hot water circulation circuit can be selected. COPYRIGHT: (C)2007,JPO&INPIT