I have a Bryant 395 BAW 036080 furnace. There is gas and there is power (the pilot light, the "sparker" and the exhaust blower fan are on). But the Maine burner is not firing. Seems like something is preventing the main burner gas to go on. Any ideas what is not allowing the main burner to fire up?

After checkng out leads to the info available on the web, the cause of the problem has been isolated to the pilot burner assembly. I will be cleaning it and may need to adjust the pilot flame size to get it working again. If these actions fail, I will need to replace the assembly.