| 摘要 |
PURPOSE:To raise the ignitability of a combustor for a quick hot water supplier, etc., by using a system in which a differential circuit is provided, positive and negative pulses are generated by making or breaking an operating switch, and resetting for the prevention of ignition and the accidental fire of a fire detection circuit during the prechecking period is allowed. CONSTITUTION:When an operating switch 9 is ON, a transistor 17 for prechecking turns ON only when a prechecking circuit 11 detects a false fire by the positive signal of a differential circuit 15, an igniting relay 14 is nonmagnetized, and the main valve 7 is closed. During the false fire detection period, a starting relay 10 is nonmagnetized instantaneously and a safe switching circuit 12 is operated. If false fire is not detected, the starting relay 10 is operated. When the operating switch is OFF, the differential circuit 15 gives off a negative pulse, and the input circuit of the fire detection circuit 8 is reset to an instantaneous accidental fire state through the transistor for resetting ignition input signal, which is ON. In this way, prechecking can be exactly made instantaneously and safe ignition process can be attained. |
