Sam J - arrived to Silver club member for fall tune up on horizontal furnace in attic. Spoke with customer and he explained there were not any cold spots in the house and thermostat is operating properly. System was running and thermostat was reading 69 when I arrived. Cycled thermostat off and began servicing system. Replaced (2) 20X25 and (1) 20X20 air filters in grilles. Removed coil cover to inspect heat exchanger and coil. Coil is clean but is rusting and shows signs of its age. Heat exchanger is free of any cracks or rust. Checked capacitor on blower motor which is good. Cycled system on from thermostat and watched for proper ignition. Then I checked amperage of inducer motor then blower motor once it cycled on. Ducts connected and insulated well, return clean of any trash or debris. Checked temperature difference at grilles, which was 45 degrees. Thermostat satisfied after several minutes after service was complete. Spoke with customer and informed him of the syst