the other little rods are the igniter and thermocouple. the gap has to be correctly adjusted for the spark, kind of like a spark plug. I found with our furnace
it seemed to be sensitive to voltage, sometimes would not work off only the battery
, but would if the converter had power to it. I've since replaced the converter, removed the furnace
, and use the space for storage. I didn't like how hot the wall got next to the furnace
when it was on, the wall to the rear that is. There is a place online, something like "Dinosaur Electronics", that may be able to help you with the circuit board. The Uhaul
manual has a wiring diagram and test procedure. My problem was the gas valve wouldn't open sometimes, and I believe it was a voltage problem.