| 摘要 |
PURPOSE:To prevent the elevation and the slight variation of the feed hot water temperature by a method wherein the hot water flow rate resistance generating in the direction of an outlet side tank from a first heat exchanger is made higher than that in the direction of the first heat exchanger from the outlet side tank. CONSTITUTION:The first heat exchanger 1 consisting of a boiler having a smoke duct 2 therein is in communication with the second heat exchanger 4 in the form of a coil-like pipe type heat exchanger. A check valve 11 is provided in a branch pipe 10 arranged between the outlet side tank 8 having a hot water discharge pipe 9 provided on the outlet side of the second heat exchanger 4 and the first heat exchanger 1. As the flow of the hot water in the branch pipe 10 is stopped by the check valve 11, the low temperature hot water from the boiler 1 is not supplied for use directly. The high temperature hot water locally boiler within the pipe type heat exchanger 4 due to after-heating after the extinguishment of a burner is circulated naturally through the pipe type heat exchanger 4 from the outlet side tank 8 via the branch pipe 10. |
