Tech arrived at a membership tune-up. Upon inspection the filter was dirty and loose in the filter box. This was allowing unfiltered air to move into the blower air. Blower area was dirty. The vinegar was poured down the drain line. The heating system reached complete ignition. The flame sensor was scorched. There was no observed surge protection. The customer was informed of recommendations today. He decided to move forward with ordering the 20*25*4 AprilAire upgrade kit. He will review the other recommendations. We will pause for parts. The system was heating upon departure.