Silver club Heating tune up on 2013 Carrier 80% furnace. Asked customer about hot and cold spots, how temperatures are keeping up and if they had turned on the furnace yet this season. Inspect Filters and they need to be changed in October. Home is heating and cooling well and furnace has not been turned on yet. Opened up furnace access panels and cleaned flame sensor. Cycled system on heat mode for a system precheck. Cycled system off and tested blower capacitor. Removed blower and checked wheel and heat exchanger. Checked flue. Checked evaporator coil and supply ductwork. Checked return ductwork and it could use a cleaning. Cycled system on and checked hot surface igniter, blower amps and inducer amps. Blower wheel is in range but running a little high at 10.4 amps, The returns are slightly undersized for the system and the filters are 2/3 used, so this may be why. Tested gas pressure and reset gas plug. Checked temperature rise and indoor delta t. System is heating properly!at this