| 摘要 |
PURPOSE:To make a titled hot water boiler not to operate when a detecting circuit is out of order, by starting a series of action as the hot water boiler after confirmation of normal action for a spark detecting circuit and a flame detecting circuit which control a solenoid valve in a gas duct at an initial stage. CONSTITUTION:When actions of a spark detecting circuit 82 and a flame detecting circuit 83 are normal, an exhaust fan 6 is driven, a prepurge timer circuit 85 is actuated through an air pressure switch 60, then an ignitor 7 is actuated, a spark is detected by a spark detecting circuit 82, gas is supplied and ignited through actuation of a solenoid valve 8. On the other hand, when either the detecting circuit 82 or 83 is unusual action is suspended after that, and a hazard, such as release of the gas is eliminated, as a thyristor 56 is kept off as it was and neither a relay 9 is excited nor the exhaust fan 6 is operated. |
