enblethen wrote:
An 84 rig should have a remote time delay relay which would start fan before power goes to the circuit board via the sail switch and thermal cutout. That would or should eliminate circuit board as primary problem.
I'm thinking this might be the problem. The thermostat is doing what it should. Something "clicks" loudly at the furnace, but I get nothing fan-wise. If I turn the thermostat down, and then back up (sometimes 2 or 3 times) it will function as normal until it needs to fire again.
The 24k BTU furnace in the rear is trying to pick up all the slack, which is not working.