| 摘要 |
PURPOSE:To optimum-control the flow to a heat exchanger and ensure the operation of a flow passage closing valve to the heat exchanger by method wherein the flow characteristics of a valve in a circuit by-passing a heating part is rendered to be discontinuous to that of the flow passage closing valve to the heat exchanger. CONSTITUTION:The heat exchanger 2 in the heating part A and a bathtub 7 are connected to a heating circuit 11, in which a circulating pump 5 is provided and midway of which a temperature sensor 14 is arranged. Feed water temperature signal from the sensor 14 controls a solenoid valve 15 arranged at the influx side of the heat exchager 2. The by-pass circuit 13, which by-passes the heating part A and in which a by-pass valve 12 is arranged, is provided by branching-off the piping upstream of the solenoid valve 15. The by-pass valve 12 is a direct-acting pressure relief valve consisting of a valve 41 which is urged, through a spring 39 by means of a pressure setting screw 37, against a valve seat 43 in flush with the bottom surface of a hole 32 communicating to an influx port 33 and has a characteristics which causes a discontinuous change between differential pressure and flow rate. |
