| 摘要 |
PURPOSE:To permit the stop of combustion in a main body when an exhaust pipe is separated from another exhaust pipe or the main body of the title heater, by a method wherein an AC voltage is impressed on the main body and the route of the exhaust pipe to conduct AC current therethrough and send a signal to a combustion control circuit by a light transmitting element, operated by the current. CONSTITUTION:When electric conduction is cut off due to the separation or the like of an exhaust pipe 3 between the shutter of a main body 1 and the route of an intermediate connector 7, a light emission diode 19a becomes non- conductive, therefore, a light receiving transistor 19b remains OFF and a pulse signal is not supplied to a terminal 20. A control unit 9 detects that the pulse signal has disappeared and stops the driving of a relay 10 while a normally opened contact 11 is opened at the same time and the conduction of a combustion air supplying fan 12, a convection fan 13 and a fuel supplying pump 14 is intercepted, thereby stopping the combustion in the main body 1. |
