Customer stated that the Main level 2003 Trane furnace would not heat, upon further inspection no error codes were found. I reset system and furnace started heating home. Made customer aware furnace is older and may be having control board issues(furnace door was also a little loose so I added tape for door switch), I also found a slightly dirty flame sensor. Customer approved the BEST option with the weekend fee and a 3 system tune up. Checked heating operations of Main level 2003 Trane, Basement 2003 Trane and Upstairs 2003 Trane furnaces. Customer recently replaced the 3-16x25x1 filters, Checked capacitor outputs and amp drawls, Inspected heat exchangers, Checked delta T, triggered safety switches, Cleaned flame sensors, Cleaned burners, and cleared drain line. Systems are operating properly at this time. Pics uploaded