Abstract: A water heater includes an exhaust hood, a heat exchange module, a main heat valve and a control valve extending downwardly in turn between a case and a plate. Inlet and outlet heads are installed on the two sides at the end of the hot water pipes respectively. Holes are punched on the case and the plate correspondingly to connect intake heads with water supply pipes going through the plate. The outlet head goes through the case and the pin connects with one water-intake hose directly. The control valve has one gas valve, one control switch and one water plate. The gas inlet of gas valve is connected with a gas can. Two pipes are installed on the water plate, which are pin connected with the intake head of the heat exchange module. With low flow capacity, the temperature of hot water output can be adjusted for direct use by a human body without mixing cold water.