Replaced that piece. I don’t have the actual “light sensor”, just a high limit switch. open at 190, closed at 150.
“I don’t have the actual “light sensor—
I don’t know how that could be as it would turn your furnace into a potential bomb. That sensor is a major safety component.
The electric eye or light sensor as you call it is located under the ignition transformer on top of the burner. It is a round black component that points toward the flame. It has wires coming out the back.
Lets say your furnace turns on and sprays fuel in the combustion chamber but it does not light. The light sensor sees this thereby causing the control to shut down the furnace after 45 seconds or so. Now imagine the furnace kept running for several minutes(with no safety) and suddenly decided to light with a huge amount of excess fuel in the fire chamber. Not a pretty sight.