| 摘要 |
PURPOSE:To determine a capacity of hot water feeding by a method wherein a degree of a combustion of gas at a burner is displayed in response to a long or short length of lit time of a display light. CONSTITUTION:A light emitting diode (display light) 9 has a first transistor 10 connected in series therewith and a current limiting resistor 11 and they constitute a display unit 8. When a set hot water temperature is high, a high electric current is flowed in a gas proportional control valve 4 (gas valve 12), so that a voltage of the resistor 14 shows a high value. Output of an operation amplifier 20 performs a high and a low operation. During this high or low operation, when the current flowing in the gas proportional control valve 4 is high, the output of the operation amplifier 20 has a short high output and a long low output, respectively. A third transistor 21 has a short turn-ON and a long turn- OFF. When the third transistor 21 is turned ON, the first transistor 10 is turned OFF, and in turn if the third transistor is turned OFF, the transistor 10 is turned ON. When a high electric current is flowed in the proportional control valve 4, i.e. a large volume of gas is supplied to the burner, a display light 9 shows a long lit time and a short diminished time. |
