| 摘要 |
PURPOSE:To make an input water temperature sensor unnecessary and manufacture the whole of the title controller inexpensively, by a method wherein feedforward operation is effected by an input water temperature, estimated by an output hot-water temperature sensor. CONSTITUTION:An input water temperature estimating unit 16 inputs the flow rate of a flow rate sensor 2 and an output hot-water temperature from an output hot-water temperature sensor 6 to estimate an input water temperature and output it to a feedforward operation unit 12. At an instance when the flow rate sensor 2 has detected the supply of hot-water and the the value of flow rate has exceeded a predetermined value Fs, the output of a comparator 17 is inputted into the clock of a data latch 19. The output hot-water temperature, detected by the output hot-water temperature sensor 6 at this moment, is inputted into the data latch 19. Simultaneously, the combustion of a gas burner 9 is started. A temperature, detected at this instance by the temperature sensor 6, is equal to the input water temperature, since a heat exchanger 5 is not heated yet. When hot-water supply is restarted immediately after stopping the supply of hot-water, the temperature of hot-water, remaining in the heat exchanger 5, is detected by the temperature sensor 6 and, subsequently, the hot-water temperature approaches the input water temperature quickly. Accordingly, a time gradient, operated in the operating unit 21 of temperature gradient, is increased and the comparing unit 22 turns a switch 23 off.
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