| 摘要 |
<p>PURPOSE:To facilitate identification whether the operation is in normal or freeze preventing operation by connecting a freeze preventing thermoswitch, the normally closed contact of an operation switch, and a primary display lamp in series and connecting a combustion control circuit and a secondary display lamp in parallel. CONSTITUTION:A primary display lamp 7 emitting red light and a secondary display lamp 9 emitting green light are accomodated together in a molding 15 and when both lamps emit light simultaneously, one display lamp seems to emit orange light. While an operation switch 1 keeps on, current is supplied to the lamp 9 and the lamp emits green light to inform the operator that the operation is in normal operating condition. When a freeze preventing thermoswitch 2 is closed while the switch 1 is open, current is supplied to the lamp 2 through a freeze preventing switch 2 and a guard resistance 8 and current is also supplied to the lamp through the thermoswitch 2, a normally closed contact 1B, and a guard resistance 6 and both lamps therefore emit light simultaneously to display orange light to inform the operator that the operation is in freeze preventing operating condition.</p> |
