On arrival I spoke with the homeowner who informed me the previous company said they needed to replace their system since there was a hole in it and they are at risk of CO poisoning. She also said she ran it last winter with no issues. I did find a test port on the flue pipe that was not sealed. I sealed it and did not see any other issues with the furnace system. I also walked around the home and my CO detector stayed at 0PPM the whole time. I also did a check on the a/c system and found the outdoor capacitor was left in the box. I secured it with plumbing strap to prevent any electrical damage.