| 摘要 |
PURPOSE:To enable a poor combustion to be eliminated rapidly by a method wherein an air fuel ratio between an amount of gas and an amount of air is changed in the case that a sensing signal obtained through a burner combustion state sensing means is less than a predetermined threshold value. CONSTITUTION:As combustion state at a burner 12 is detected by a burner combustion state sensing means 60 and its detected signal is less than a predetermined threshold value, an air fuel ratio between an amount of gas and an amount of air is changed by an air fuel ratio changing means 36. In addition, when the detected signal is less than a minimum threshold value, combustion is stopped by a combustion stopping means 30. In this case, a variation in a burner flame in respect to CO/CO2 ratio is detected by a variation in electromotive force of a thermocouple 78 and then the air fuel ratio is changed in response to the output sensing signal by increasing an amount of air in respect to an amount of gas or decreasing an amount of gas without changing the amount of air. With such an arrangement as above, an incomplete combustion caused by fin clogging at a heat exchanger 14 as well as lack of oxygen within a room is rapidly eliminated. |
