that pre air X is your Induced Draft that pressurizes the burner chamber...the 4" round silver dish with the 2 wires going to it and a tube from the ID duct isn't proofing out to cycle the heat might be stuck from last winter or tube might have a bug inside...with the heat calling take on wire off the pressure switch and touch it with the other see if you get spark ignition and main burner cycle then remove.... burner should go off..so ever time you retouch it the ignition will start for the pilot.....check the tube the rounds on the squirrel within the ID blow lightly into the tube pulled out of that duct see if it clicks back and forth...lets hear back
Linear Mode
