| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a hot water storage type water heater with an empty bathtub heating preventing device for determining that an empty bathtub may be heated while using an existing metal hot water storage tank as it is, by detecting the reduction of a water level in the hot water storage tank even if the water level in the hot water storage tank is higher than a heater installation position. <P>SOLUTION: An electrode 28 is arranged in contact with water in a mixing valve device 11. Water is filled in the hot water storage tank 1 and in a water path of a distribution pipe 9, and an energizing circuit 43 is provided for making a current flow through a first connection circuit 35 and a second connection circuit 29. An estimating circuit 47 estimates the reduction of the water level in the hot water storage tank depending on whether the current flows or not in the energizing circuit 43 and a detecting circuit 45. When the estimating circuit 47 determines the reduction of the water level, an alarm signal is outputted to a heater control circuit 8 to stop the energization of a heater 7. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
