| 摘要 |
PROBLEM TO BE SOLVED: To suppress adhesion and deposition of scale to a water heat exchanger by increasing and decreasing a circulation flow rate while securing water flow of a predetermined flow rate upon boiling operation.SOLUTION: A storage type water heater includes: a hot water storage tank 8; a water heating heat exchanger 4 for heating water in the storage hot water tank 8 to turn it to high temperature water; a heating circulation circuit the one end of which is connected to the lower part of the storage hot water tank 8, in which a heating circulating delivery pump 10 and the water heating heat exchanger 4 are installed in the middle, and the other end of which is connected to the upper part of the storage tank 8; a control means upon boiling operation for controlling the delivery pump 10 such that a temperature of hot water heated by the water heating heat exchanger 4 becomes a predetermined boiling target temperature; and a control means for generating pulsation to water flow in the water heating heat exchanger 4 by increasing and decreasing water delivery amount by means of the delivery pump 10, wherein the control means controls one or both of an interval and an amplitude of the pulsation in accordance with the boiling target temperature. |
