| 摘要 |
PURPOSE:To secure a proper draft quantity with respect to an actual exhaust air resistance by storing a reference fan motor current with respect to a reference exhaust air resistance of a burner, and correcting a motor drive voltage in a direction of reducing a difference between the reference exhaust air resistance and an exhaust air resistance in the actually installed burner. CONSTITUTION:A predetermined reference fan motor drive voltage is applied to a DC fan motor 3b by a motor reference drive voltage setting part 11, and a current flowing through a motor 3b is taken into a controller 10 to detect the voltage by a voltage detecting part 12. The difference between the detected voltage and the reference voltage is computed by a voltage difference computing part 13. This voltage difference corresponds to the difference between the reference exhaust air resistance of the fan and the actual exhaust air resistance. The voltage difference data obtained by the voltage difference computing part 13 are transmitted to a motor drive voltage detecting part 14 compute the quantity of correction to be added to the motor drive voltage. In a motor drive voltage computing part 15, the fan motor drive voltage is computed in correspondence with the set hot water temperature, and at the same time, a final motor drive voltage is computed by adding the quantity of correction obtained from the motor drive voltage correcting part 14 to the voltage computed. |
