I have a Lennox Value Series Unit. I don't know the exact model #...if someone can tell me where to look for it, I can try to find it.
It worked perfectly fine for the AC this summer/fall, but when it came time to switch over to heat (gas), it wouldn't work.
When you turn on the thermostat, the unit turns on, the blower starts and then it makes a clicking noise as it tries to light. It will click, kick off, come back on, click again, kick off, etc. Everything (thermostat, blower, etc.) seems to work fine, except for lighting. The filters are new.
I haven't taken the front off of the unit because I don't want to end up causing a bigger problem. The only lights I can see are two green ones towards the top of the unit that blink.