| 摘要 |
PURPOSE:To keep the air-fuel ratio constant and to obtain a favorable combustion efficiency by a method wherein the amount of combustion is limited forcibly when it reaches the maximum rate and the quantity of combustion air is also limited in association with the limitation of the amount of combustion. CONSTITUTION:A signal corresponding to the temperature of hot water detected by a thermister 12 is detected by a temperature detecting circuit 15 and is deducted from a signal determined by a temperature setting device 16 at an adding point A (14). Then the signal is transmitted to a temperature adjusting circuit 17 and then to an adding point B (24) where the signal is added with the output of a differential pressure comparator 20 transmitted through an ON-OFF switch 23, to thereby produce a synthesized signal. In this case, if the synthesized signal is found positive, it is judged that the temperature of hot water is lower than the temperature determined by the temperature setting device and so that number of revolutions of a blower 1 is increased by an r.p.m. adjusting circuit 25 to thereby increases the quantity of combustion air. On the other hand, if the synthesized signal is found negative, the number of revolutions of the blower 1 is reduced and at the same time, a control circuit operates to close a pressure control valve. |
