| 摘要 |
PURPOSE:To detect a reverse flow and to stop gas combustion by attaching a temperature sensor to the passage of a flow rate sensor before a heat exchanger, measuring temperature around the exchanger at the time of heating of the exchanger, and stopping heating by a controller when the water in the passage before the exchanger reaches high temperature. CONSTITUTION:Water is normally fed in a direction of an arrow in the drawing, a water stream is detected by a flow rate sensor 1, a water temperature signal from a water sensor 6 is fed, a gas combustor 4 is so burnt by a controller 5 that the temperature of the sensor 3 becomes necessary hot water temperature, and to control the combustion amount. In this case, since the sensor 6 always detects the temperature of the water before heating, it should detect lower temperature than the hot water temperature to be detected by a hot water sensor during the combustion of gas. However, when the water reversely flows in a heat exchanger 2, it becomes reverse to an arrow in the drawing. Thus, when the gas is burnt, the detected temperature of the sensor 6 always becomes higher than the detected temperature of the sensor 3. In this case, the controller 5 stops the combustion of the combustor 4. |
