| 摘要 |
PURPOSE:To prevent the pressure in a hot water circuit from abnormally rising to aim at avoiding a breakage, etc. in a heat-exchanger, a hot-water pipe line. etc. even if a heater is operated while a valve disposed in the circuit is left to be opened, by disposing a check valve in the valve element of the valve. CONSTITUTION:In the case of that during the off-season or upon failure of a heater cooling water circuit, valves 1A, 1B are closed to divide the cooling system into an engine 3 side second hot water passage 10B and a heater side first hot water 10B, and then a preheating type heater 5 is erroneously operated again while the valves 1A, 1B are left to be closed, the pressure in the hot water circuit 10B rises due to the combustion heat from the preheating type heater 5. However, when the pressure rises and exceeds, for example, 0.5kg/cm<2>, a disk 31 of a check valve 30 disposed in the valve 1B is opened under pressure to transmit the pressure into the engine 3 side second hot water passage 10A. Further, the pressure rises above the valve opening pressure of a radiator cap 2a, the pressure is therefore, discharged to the outside, thereby the pressure of the cooling water system will not rises above the valve opening pressure. Accordingly, a heating apparatus, pipe line component parts may be prevented from being broken due to abnormal pressure. |
