I'm about at my wit's end. I can't get my raypak 406a to fire up. The pilot lights and sometimes the burner will light for a few seconds. System then restarts at pilot, but this time will not light. After a while I get Ignition failure indication. Then I can't get much to happen until I wait a while (many minutes). I've replaced the pilot assembly because it looked like a flame rectification problem. No change in symptoms. I've tried a new control board, but this did not change the symptoms. The only thing left I can think of is to change the gas valve. Any suggestions on how to verify that this could be it before I take this step. You guys have been great in the past; I've tried to read all the past threads I can find, but I'm running out of ideas. I'd so much appreciate some help.