| 摘要 |
PURPOSE:To ensure safety in a way that a trouble is detected when it occurs and a power circuit is disconnected, by a method wherein a projection, formed on the bottom of an evaporating cylinder, is extended outside a burner case, a fuse is attached to the end part thereof, and a draft passage for cooling is installed on the under surface. CONSTITUTION:During normal operation, a temperature fuse 6 is positioned in a draft passage 13 for cooling, and thereby it is cooled by suction of a blower 10 for convection. By a cooling effect, temperature is almost prevented from increase, and thereby a wide margin can be left in the operating temperature of the temperature fuse 6, and this prevents the fuse from early fusing. Meanwhile, in case a relay contact, which controls energization of a sheath heater, is welded or a combustion controller malfunctions to leave the sheath heater in an energizing state, a metal 5, located outside a burner case 2, is rapidly increased in temperature through the working of a projection 4 formed on the under surface of the evaporating cylinder 1, resulting in fusing of the temperature fuse 6 and disconnecting of a power circuit. |
