PURPOSE: To permit to control the flow amount of circulating water at a constant flow amount without affecting on hot-water supplying time by a method wherein the water is flowed to circulate while a burner is burnt intermittently.
CONSTITUTION: When an operating switch 17 is put ON under the condition that the hot-water delivery valve 10 of a hot-water supplying instrument is being closed, a base solenoid valve 11 is opened and a pump 3 starts the rotation thereof simultaneously. A delivered hot-water temperature sensor 8 detects water temperature and a solenoid valve 12 repeats the opening and closing thereof to begin with the intermittent combustion of the burner 6. Water in a pipeline flows to circulate from a feed water pipeline 2 so as to return to the upstream side of a water amount sensor 7 through a return pipeline 4 and is heated during passing through a heat exchanger 5. The flow amount of circulating water is controlled to an objective flow amount by a control base panel 15 through controlling the phase of a motor for the pump 3 electrically. The intermittent combustion of the burner 6 is controlled by the control base panel 15, therefore, the water is heated up to a set temperature and the temperature is maintained. When the hot-water side valve of the hot-water supplying instrument 10 is opened, the hot-water, being heated up to a set temperature, may be supplied.
NAKAMURA HISASHI
MAKITA ATSUO
