I have had to replace the Ignition Control Kit twice in 8 years on my Lennox Furnace. The first time was within the warranty the second time was last year. The Lennox Ignition controller is a bad design so they replaced it with a Honeywell Ignition Control Kit G20/G20R/G23/G26.
I hope this one doesn't quit on me at 2:00am in the morning like the last one did. They are $100.00 a piece