| 摘要 |
PURPOSE:To adjust an air-fuel-ratio to a proper value and to enable a burner to perform a normal combustion by a method wherein when a pressure within a combustion box is higher than a pressure of a room, an amount of feeding air of an air feeding fan is increased in reference to a pressure differential signal got from a differential pressure sensor. CONSTITUTION:A differential pressure sensor 6 for outputting a signal corresponding to a differential pressure when a pressure in a combustion box 3 is higher than a pressure in a room A is provided. An amount of feeding air of on air feeding fan 5 is increased in response to a value of the differential pressure signal got from the differential pressure sensor 6. More practically, it is provided with a differential transformer 8 for comparing a pressure in the combustion box 3 with a pressure in the room A to cause a movable core 7 to be displaced in response to the differential pressure, and with an adding circuit 10 for adding a signal of the set number of revolution got from the number of revolution setting circuit 9 for an air feeding fan 5 to an increased amount signal of the number of revolution corresponding to the amount of displacement of the movable core 7 outputted from the differential transformer 8 when the pressure in the combustion box 3 is higher than the pressure in the room A. The air feeding fan 5 is controlled by the number of revolution adding signal outputted from the adding circuit 10. |
