I have a 6 year old Lennox Value Series, model C23-31-1.
When I turn up the themostat the unit does not go on automatically. Periodically, I hear the pilot light going on for about 5 to 10 seconds then it shuts off, then it goes on for about the same time and shuts of. This repeats and then sometimes it stays on and sometimes it doesn't.
I will eventually call a repairman but would like to know what I am taking about when I do. If anybody has any ideas of what could be causing this, I'd greatly appreciate the advise.
P.S. I have had my thermostat changed in the last few years and also had an internal modual changed last year. I have not found this unit to be very reliable.