| 摘要 |
PURPOSE:To permit to obtain a desired hot-water temperature surely even in case there is variability in equipments by a method wherein the minimum conduction time is set and a necessary conduction time is changed in case the necessary conduction time is shorter than the minimum conduction time. CONSTITUTION:When the conduction of midnight electric power is started, the count of a nighttime timer (HN) is started and the necessary conduction time (Hs) as well as the shift time (HP) of conduction starting are operated. In case the necessary conduction time (HS) becomes shorter than 2 hours, the necessary conduction time (HS) is changed and the shift time (HP) is operated. The characteristics of water temperature (TW) and the shift time (HP) are shown in the diagram at two points of 85 deg.C and 55 deg.C of set hot-water temperature (TS), for example. In this case, the minimum conduction time reaches 2 hours at TW=67 deg.C when TS=85 deg.C while TW=37 deg.C when TS=55 deg.C and HS=2 hours at all time when the water temperature is higher than 67 deg.C. Accordingly, the conduction time of a heater is secured at least 2 hours and even in case one hour of error is generated in the variability of the equipments, the conduction time of 1.2 hours may be secured. |
