| 摘要 |
PURPOSE:To prevent failure, and trouble at the time of abnormal condition, by always comparing the current signal from a proportional valve current detecting circuit with the setting current signal calculated in accordance with the combustion rate. CONSTITUTION:A proportional valve currnet detecting circuit 9 outputs a proportional valve current signal to a proportional valve driving circuit 7, as well as to output one to a comparator 6. A combustion controlling circuit 4 calculates the rate of combustion, and outputs a setting current signal to the propoetional valve driving circuit 7, as well as to output one to the comparator 6. The compares the proportional valve current signal with the setting current signal, and if a deviation exceeds a predetermined value, the comparator recognizes it as an abnormal value, giving a signal to timer circuit 5. The timer circuit 5 actuates a timer, reveiving an output signal from the comparator 6. If the comparator continuously feeds output signals to the timer by a large deviatio unitl the set time comes up to an end, the timer outputs an alarm signal to the combustion controlling circuit 4, stopping combustion in a burner unit. |
