| 摘要 |
PURPOSE:To prevent rapid increase in gas volume at the changing of the set value and check abnormal combustion by means of an ignition retarding circuit which is adapted to delay the rising speed of the drive output of a proportional valve of the burner according to the amplified rise in the output as a result of comparing the temperature of hot water and the set value. CONSTITUTION:Thermosensitive elements 3 and 3' comprising a diode varister is provided at the downstream of a heat exchanger 1 to be heated with a burner and between the inlet and the outlet thereof. The output of the elements is amplified by an operation amplifier 6 and delayed with an ignition retarding circuit 7. Then, the drive output is amplified with a power amplifier 8 to control a proportional control valve 4. |
