Kenmore Elite GAS Range. Model:79079013101

I have had the range since it was new A few years ago the oven bake heating burner (bottom) would no longer ignite and heat the oven. The stovetop burners are functional as well as the Broiler and the bake igniter was glowing a bright orange.
In any case, I purchased a new igniter and installed it. It glowed the same color as the original igniter but the bake heating burner still would not ignite.
I called a service company. I was at work and my wife met with the service person when they arrived. Later in the day, my wife called and told me the oven was fixed. The Service person was only there for a few minutes and fixed it she told me. She also told me that the Service person was not going to charge us because I had already pulled the oven away from the wall and the fix was so easy he would feel bad to charge us for the call. The oven worked for a year or two and then the bake heating burner once again would not ignite. I checked the pressure regulator - that small value that can be in the up or down position, I have tried it both ways. (What position SHOULD it be in lever up or down?). The top burners still work as well as the Broiler.
Can anyone tell me what the Service person could have done that was so simple?
Please - many thanks in advance.
John