| 摘要 |
PURPOSE:To restrict a consumption amount of gas under an anti-freezing mode for a hot water circulating type heating device and to prevent a problem of forming dew at fins of a heat exchanger. CONSTITUTION:In the case that a water temperature (th) within a hot water circulation passage 12 is not higher than a surplus heating prevention temperature (t2) and an inner timer 36 is timed up irrespective of the fact that a combustion control under a supplying of a minimum small amount of gas required for preventing a freezing is continued for a specified period of time T0 at a controller 38, the controller part 38 releases a small amount combustion control, proportionally combustion controls of a gas burner 16 with a predetermined temperature higher than the surplus heating preventing temperature (t2) being applied as a target value, and a water temperature in the hot water circulation passage 12 is forcedly increased up to the surplus heat preventing temperature (t2). With such an arrangement, a fine volume combustion control is prevented from being continued for a long period of time. |
