I have a 1997 Comfortmaker GNL125 that has had periodic problems starting up from being off long term. In the past, shutting off the thermostat for 5 - 10 minutes has fixed the problem. However, now it will not start @ all. The combustion air blower starts and the "hot surface ignitor" glows. After that, it does not seam to cycle any further. . . no clicks or any other indication that the pilot is trying to light. I assume the problem is with the Gas Valve or a vacuum tube. A place to start or other comments would be great. I already have a call into a Service Tech who is supposed to call back, but I want to get a little more knowledgable befor I talk to him further.
After cleaning the sensor, making sure there was no obstructed vacuum hoses, etc., I was positive it was in the gas valve. I had a tech come out & he confirmed my suspicion. New "Smart Valve" = $166 , Service Call = $65 , warm, cosy house = priceless