Performed fall tuneup in gas furnace, this is first visit on new contract. System is operating properly at this time. Carbon monoxide test passed at 0ppm. Homeowner had concerns with condensation around flue pipes going into the attic. Found portion of flue cracked. Scheduled flue repair for 11/18 8-9 arrival. Ac fan is not operational- decision was made to wait until spring to address issue.