Heat performance tuneup times four systems. Inspect blowers, evaporators and ductwork. Test all safety features high limits and rollouts. Living room area system is dangerous to operate the furnace at this time. In first stage I recorded 6 ppm carbon monoxide in second stage, I recorded 8 ppm. This furnace is very dangerous to operate. I advised Jim to not operate this furnace until he’s made a decision on replacement. I am leaving estimates for furnace only and options for complete replacement. I am giving a special deal on a 20 seer system at 18 seer pricing.