| 摘要 |
PROBLEM TO BE SOLVED: To dispense with an electric actuator for driving a valve to control circulation of water to a heat exchanger.SOLUTION: In a water circulation device for supplying cooling water (hot water) to a heat exchanger 5 for heating by a second water pump 6 driven by an electric motor, a suction side and a discharge side of the second water pump 6 are connected by a pressure transmitting circuit 7, and a differential pressure valve 8 is disposed on a connecting portion of a discharge-side region of the second water pump 6 and the pressure transmitting circuit 7 in a second water circulation circuit 22. When the second water pump 6 is operated, a valving element 81 is moved in the valve opening direction by pressure difference between front and rear parts of the second water pump 6, and the second water circulation circuit 22 is opened. On the other hand, when the second water pump 6 is stopped, the valving element 81 is moved in the valve closing direction by a spring 82, and the second water circulation circuit 22 is closed. |
