| 摘要 |
<p>PURPOSE:To reduce a running cost by a method wherein an electrical heater energization allowing means allows an electrical energization to be carried out at a heater during a night-time period set by a night-time zone setting means and only the electrical energization of the heater is carried out for the time set by a day-time additional heating time setting means during a day-time zone. CONSTITUTION:At a step 1, a night-time zone setting means 5 judges whether or not the present time is in a night-time zone. If the time is in the night-time zone, a heater electrical energization allowing means 7 allows an electrical energization of the heater. Then, a temperature sensing means 3 detects a hot water temperature. If the detected hot water temperature is lower than the set temperature, a temperature control means 4 turns on a heater 1 and at the same time a heater electrical energization time calculation means 8 counts a heater electrical energization time. In addition, at the step 1, if the time is not the night-time zone, a day-time additional heating time accumulation time setting means 6 inputs a day-time additional heating time setting t0 and then an accumulated value t1 of the heater electrical energization time accumulated by a heater electrical energization time accumulation means 8 is inputted. Then, the heater electrical energization allowing means 7 compares the day-time heating time setting t0 with the accumulated value t1 of the heater electrical energization time. If t0>=t1 is attained, the heater electrical energization is allowed and in turn if t0<t1 is got, the heater electrical energization is prohibited.</p> |
