Performed comprehensive furnace tune-up on 7-year-old unit. Adjusted gas train pressure from 3.72 inWC to 3.50 inWC, cleared debris and spiderwebbing from condensate drain line and trap. Verified proper operation of inducer motor, pressure switch, control board connections, and thermostat. Combustion CO measured at 19 ppm, with filter in moderate condition. System functioning normally with no immediate concerns.
