| 摘要 |
PURPOSE:To improve safety and a control performance, by a method wherein a coolant pressure is prevented from attaining an abnormal level. CONSTITUTION:In case of the water temperature at an outlet of a heat exchanger 7 for hot water feed is low, an amplifier 24 is increased in its output, and an amplifier 27 of a motor control signal output part has an OV output to stop running of a driving motor. In case of the water temperature at an outlet is high, the output of the amplifier 24 decreases, the output of an amplifier 27 also increases up to a power source voltage, while a driving motor 10 runs at a high speed to flow a quantity of circulating water by the value more than necessary. In order to correct an amount more than a response lag of a temperature detecting element 9 itself by a differential output at the starting, a state in which the corrected temperature attains the water temperature at the outlet of the heat exchanger 7 for hot water feed is detected earlier than the actual state. Thus, before a coolant pressure attains an abnormal pressure, the driving motor 10 is increased in the number of its revolutions, and circulating water is increased in quantity to suppress the rise gradient of the coolant pressure and prevent the coolant pressure from attaining an abnormal pressure. |
