I have a york diamond 80 that starts and runs grate for a wile some times 20 hours or more with no issue then shuts off and the red light comes on and stays on indicating a replace controller condition all safeties test out OK nothing has needed to be reset I guess I'm just wondering if it relay needs a new controller or if its something else messing it up

Thanks B

OK have been watching the unit operate for a wile now here is what I am seeing inducer starts runs for a bit then ignighter starts to glow then click fuel starts to flow and ignights now a few seconds in to the burn the red led flashes once fuel continues to burn then the main blower kicks in and unit heats house till thermostat clicks off then gas off with inducer then 90 or so seconds later main blower kicks off every thing seams fine other than the red flashing led one means lock down check furnace but I thought that was supposed to shut it down? As of now its running and it may keep running till after I get home from work tommarow or the house may be cold in the morning there is no set pattern any ideas?