| 主权项 |
1. A hot water supply device comprising;
a burner unit; a heat exchanger, for applying heat to water with combustion gases supplied from said burner unit, including a plurality of fins, a heat exchange tubing and a heat exchanger casing; a temperature detector for detecting a surface temperature of the heat exchanger casing; and a determination means that determines that scale has built up in said heat exchange tubing of said heat exchanger when a temperature detected by said temperature detector is greater than a set temperature; wherein said burner unit comprises a plurality of combustion tubes that are disposed in a predetermined arranging direction, said plurality of combustion tubes including at least one always combusting combustion tube that is always performing combustion while hot water being supplied; said heat exchanger comprises a lower heat exchange region that is disposed so as to face directly to said burner unit from above, and an upper heat exchange region that is disposed on an upper side of said lower heat exchange region and heats hot water heated by said lower heat exchange region; said heat exchange tubing of said lower heat exchange region is constituted by means of connecting, with a plurality of U-shaped link tube portions, a plurality of straight tube portions extending toward said arranging direction that are disposed at given intervals in a direction orthogonal to said arranging direction; and said temperature detector is disposed on a surface portion of said heat exchanger casing in a neighborhood of a downstream side portion in a hot water flow in said lower heat exchange region, said surface portion being closest to said always combusting combustion tube. |
