I have an ancient Trane XE80 furnace in the basement. It has been slowly falling apart for years and i have been piecing it back together. This year, this week to be specific, it has decided to only intermittently give us heat.
There is no error code on the board, just a normal call for heat. The HSI works fine, the gas clicks on and will ignite at times. Sometimes it is a inconsistent ignition sequence that keeps repeating until only the blower is working. Other times it follows the expected route of heating until it has reached the correct temp.
The control board is new as of last year. The air filter is new as of a week ago. There doesnt seem to be any blockages. The flame sensor was just cleaned. Any help would be GREATLY appreciated.
P.S. If you can please post pictures because i have no manual that points out specific parts.