| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a storage type water heater of high reliability which can detect the heat insulation deterioration of a hot-water storage tank surely with high precision by a sensorless manner, and can take measures in an early stage. <P>SOLUTION: The storage type water heater 1 including the hot-water storage tank 10 of a heat-insulated structure to store hot water produced by a heating device 2 includes a hot-water storage tank heat insulation deterioration detecting circuit 16 that stores an average operation time per day of the heating device 2 in a period set previously from a time of the installation of the storage type water heater 1 as a past record of the past operation time and determines that the heat insulation of the hot-water storage tank 10 has deteriorated when the present value to the past record exceeds the set value by comparing the average operation time per day after that time with the past record by making it as the present value. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
