| 摘要 |
PURPOSE:To prevent abnormal rise in temperature in a gas vaporizing part, when a wire disconnection is detected in a thermistor for detecting the temperature in the gas vaporizing part, by stopping all operations after quenching the gas vaporizing part, by setting the opening of a damper to control the air rate for combustion at the maximum, after de-energizing the vaporizing heater. CONSTITUTION:When a thermistor 2 for detecting the temperature in a gas vaporizing part is broken in a condition that liquid fuel is vaporizing and burning, a point (a) turns OV, and input relations among comparators 9-11 are made to be Va>Vd>Vc>Vb. Accordingly, the output from an OR circuit 14 is 1 at the time when a transistor Tr20 is turned OFF, after the set time elapsed in a timer circuit 21. Then Tr19 is turned ON, and a relay 13 for controlling a vaporizing heater is made unexcited, to stop energization to the vaporizing heater. At the same time, a relay 36 for controlling a burner motor is energized, and a damper is opened at the maximum by a solenoid 44 for controlling a damper being not energized, as well as to drive the burner motor, and all operations are stopped after the set time elapsed in a timer circuit 26. |
