I don't know much about furnaces. Mine is a Goodman GMT090-3A. It is five years old and it has failed 3 times. The igniter was replace twice and the last time, the serviceman said the gas valve was faulty. The part was under warranty but he didn't happen to have one in his truck so he banged on it a couple of times and it started working. He was then going to charge me $200 to to come back with the new valve that the warranty covered. I thought that was ridiculous considering the warranty and considering I paid him $100 to come bang on my furnace!

So, after the furnace had not run for several weeks, now it won't go on. The blower goes, but then everything shuts off after it doesn't ignite. The trouble shooting light does not blink so that is no help. I am not sure where to look to see if the igniter is "glowing" I haven't seen anything in there glowing.

So, how do I tell if it's the igniter or the valve?

Is there somewhere that I can find a diagram to tell me which gizmos are which in there? I had to do some detective work to even find out the brand as there are no stickers indicating that information!

If the burner lights but does not stay on try cleaning the falme sensor.

Option B get a better repair man.