| 摘要 |
PURPOSE:To prevent discharge of green gas due to poor ignition, by providing a control circuit which shuts off a gas main electromagnetic valve when the starting of the use of hot water is compared with the temperature of hot water after lapse of tens seconds, and a temperature difference is increased to a value higher than a given value. CONSTITUTION:The pilot flame of a water heater, during the use of hot water, has size large enough to allow spread of flame to a main burner 5. But, when choking of a pilot burner 6 occurs with age, an electromagnetic motive force is narrowly generated to a thermocouple 4, and is increased to intensity being high enough to allow holding of the pilot burner 6. In which case, when hot water is fed, flame is not spread to the main burner 5, and green gas is left being produced. However, when the flame is not spread to the main burner 5, hot water is not fed from a faucet. Therefore, the state is detected by a control circuit in an electric accessory box 2, and a gas main electromagnetic valve 3 is immediately shut off, and this enables prevention of green gas from discharge. |
