DETECTION AND INDICATION OF AMOUNT OF HOT-WATER REMAINING IN HOT-WATER RESERVING TYPE ELECTRIC WATER HEATER

PURPOSE:To permit to indicate the amount of remaining water in accordance with the usage of hot-water individually and selectively by a method wherein the amount and temperature of hot-water remaining in a hot-water reserving tank as well as the temperature of water supplemented into the tank are detected to operate the amount of hot-water when the hot-water of a reference temperature is obtained by mixing the remaining hot-water with the supplementing water. CONSTITUTION:A plurality of thermistors A1-A4, as a means to detect temperatures, are arranged on the side wall of the hot-water reserving tank 1 at every constant volume sequentially from the upper part of the tank and the temperatures are detected as the change of resistances due to heat given to respective thermistors. When the amount of remaining water is indicated by (d), the constant volume is by (d0) and the number, indicating high output in the output from a comparator, is indicated by (n), the amount (d) is given by a formula d=d0.n and, thus, the amount of hot-water having a temperature higher than some temperature is obtained easily. Respective switches SW1... are separated into several steps such as washing water (35 deg.C), bathing water (45 deg.C), steamed towel (60 deg.C), the highest temperature hot-water (80 deg.C) or the like respectively. On the other hand, volume indicating lamps LED1... are provided with stepped volume indications, whereby the indicating lamp is lightened to indicate a remaining volume correctly by setting in the switch SW2 how many liters the hot-water of yesterday is remaining in case it is estimated by the temperature of bathing hot-water temperature (45 deg.C), for example.