| 摘要 |
PURPOSE:To make it possible to controll the gas pressure with the reduced electric power, by controlling the motor of an electrically driven pressure proportional controlling valve, which regulates the gas flow by changing the spring power, according to a load signal. CONSTITUTION:While water, which streams through a heat exchanger 11, is not heated yet, resistance of a temperature detecting element 12 stays in the maximum value, a motor 26 of an electrically driven pressure proportional controlling valve 34 is revolved through a proportional controlling circuit 37, a slide pin 22 is pushed downward by a cam 25, and the combustion quantity of a burner is increased to the maximum. As a signal of a position detector, which detects the motion placement of a movement transmission mechanism, is input into the proportional controlling circuit 37, the motor 26 can be stopped at that position. When the hot water temperature rises and resistance of the temperature detecting element 12 becomes lower, the motor 26 is revolved in reverse direction as the supplying gas pressure to the burner becomes lower. If the heated water flow is increased/decreased, or the water temperature is changed, the hot water temperature is kept at an almost fixed value, because the proportional controlling circuit 37 controls the motor 26. |
