| 摘要 |
PROBLEM TO BE SOLVED: To provide a storage water heater that reduces the largest number of recovery openings that recover returned hot water from a user side heat exchanger to a hot water storage tank, and reliably suppresses the shortage of hot water without requiring a temperature sensor for detecting a temperature of the returned hot water, and maintains the efficiency of boiling operation high.SOLUTION: A storage water heater includes: an upper part returning circuit that returns hot water taken from a hot water storage tank 10 to an upper part area of the hot water storage tank 10 through a user side heat exchanger 22; a lower part returning circuit that returns the hot water taken from the hot water storage tank 10 to the lower part area of the hot water storage tank 10 through the user side heat exchanger 22; a channel switching means that switches the upper part returning circuit and the lower part returning circuit; and a control part 70 that performs lower part returning heating operation that circulates the hot water taken from the hot water storage tank 10 to the lower part returning circuit for a predetermined time to replace the hot water in the lower part returning circuit, and then starts upper part returning heating operation by switching to the upper part returning circuit. |
