Tech arrived at a tune-up. Upon inspection the capacitors were within specs. The condenser fan motor was recently replaced. The contactor was in working condition. The condenser coils were hosed off to assist with air flow across the coils. The filter was clean. The blower area was dirty. The Delta was within range. The flame sensor was scorched. The drain pan was rusting through. The was a small amount of water in the drain pan. The drain was clear and bleach was poured. The customer was informed of recommendations today. They were informed of the drain system condition and decided to move forward with adding a treatment strip to help keep the drain system clean. The system was functioning upon departure.