Showed up for a membership super tune-up checked everything indoor and outdoor changed their filter flushed the drain line with white vinegar and hot water in cooling mode I discovered they were significantly low on refrigerant so cool was only at 1.4° when I should see something between a six and a 10 and heating mode the inducer motor was producing an audible noise the entire time it was running suggesting failure could be coming soon all of the components checked out and we're working as they should current Delta is 21° I did bring it to their attention that my carbon monoxide detector was reading three parts per million we discussed the options of adding refrigerant and replacing the inducer motor we also discussed the cost of repairs the last few years and the option of full replacement they would like to have some time to think about their options I told them I would follow up with them and see if they would like to sit down with a comfort advisor