| 摘要 |
PROBLEM TO BE SOLVED: To execute a freeze preventing operation suppressed in reduction of a heat quantity in a hot water storage tank.SOLUTION: A storage type water heater includes: a hot water supply external heat exchanger 3 for heating flowing water at a secondary side while using hot water/water, in a hot water storage tank 2, circulating at a primary side as a heat source to supply hot water; a heating branch pipe 24 branched from a heating return pipe 14 and connected with a downstream side of a primary-side pump 7 of a primary-side return pipe 6; a heating switch valve 25 for switching whether hot water/water from the heating return pipe 14 is returned to an upper portion of the hot water storage tank 2 or a lower portion of the hot water storage tank 2; freezing temperature detecting means 23 detecting whether a temperature is lowered to a temperature having a probability of freezing hot water/water; and control means 36 executing a heating-side freeze preventing operation to drive a heating circulation pump 16 and heating means 11 in a state that the heating switch valve 25 is switched to the heating branch pipe 24 side, when the freezing temperature detecting means 23 detects the lowering to a prescribed temperature having high probability of freezing. The primary pump 7 is disposed in adjacent to a lower portion of the hot water supply external heat exchanger 3, and a connection point of the heating branch pipe 24 and the primary-side return pipe 6 is positioned at a lower part of the primary-side pump 7 in adjacent thereto. |
