AUTOMATIC HOT-WATER SUPPLIER PROVIDED WITH FUNCTION OF SAFE AND ADDITIONAL HEATING

PURPOSE:To effect additional heating operation safely, by a method wherein a circulating pump is stopped when a time, set by an additional heating continuing timer, has elapsed or the value of a measured bathing hot-water temperature has become higher than the value of an additional heating operation stopping temperature, preset in a control unit. CONSTITUTION:When the additional heating switch 5 of a sub controller 36 is put ON and the value Tm1 of a measured supplying hot-water temperature, detected by a supplying hot-water temperature sensor 30 provided in the heat exchanger 11 of the main body 10 of a hot-water supplier, is higher than the value Ts5 of an additional heating operation permitting temperature, set in a control unit 31, a circulating pump 18 is started and bathing hot-water is circulated between a circulating flow passage B and a bathtub 16 while exchang ing the heat thereof through the heat exchanger 11 whereby a bathing hot-water temperature is risen gradually. When the value Tm2 of a measured bathing hot-water temperature, detected by a bathing hot-water temperature sensor 29, becomes equal to or higher than the value Ts5 of an additional heating continuing timer starting temperature, the operation of the additional heating continuing timer is started to stop the circulating pump 18 automatically and prevent the danger of overheating when either a set time has elapsed or the value Tm2 of a measured bathing hot-water temperature has become higher than the value Ts6 of an additional heating operation stopping temperature.