Our furnace was about 15 years old and hadn't been inspected or cleaned for a few years, so I called Service Experts. Jonathan arrived at the appointed time, and the first thing he did was to check the CO emissions at the exhaust. It was well above the maximum allowed, so he was obligated to red tag it. Instead of selling us a major ($1400?) repair job, he advised us that the manufacturer (Carrier) had issued an extended warranty on the condensing heat exchanger, provided a copy of the Bulletin, and checked our serial number to confirm our equipment was covered.