| 摘要 |
PURPOSE:To maintain the temperature of hot water to be supplied at a set value even in the coldest season by a method wherein in the coldest season the flow rate of feed water is controlled to maintain the maximum flow rate of fuel while under normal conditions the flow rate of fuel is controlled to maintain the maximum flow rate of feed water. CONSTITUTION:Both the signal of a calculating unit 6 outputted as a result of the comparison of the signal of a temperature sensor 3 of hot water to be supplied with the set value TSP and the signal of a feed water temperature sensor 2 are inputted in a sensing unit 10 and in a controlling unit 11 respectively in order to control a fuel controlling unit 4 to supply fuel to a burner 5 under normal conditions. When the feed water temperature lowers below the critical temperature for controlling TMIN in the coldest season, the sensing unit 10 outputs the signal to actuate the fuel controlling unit 4 to send the maximum fuel to the burner 5 and to control the opening degree of a feed valve 8. |
