I thought I would squeeze in a related question.
Why are some of the 75 gallon units listed as NOT having FVIR? The spec sheet for the AO Smith FCG-75 and FCG-100 models has a footnote saying “Not equipped with C3 Technology” (their name for FVIR). I understood that the larger heaters were granted a longer time for adoption, but that date was years ago.
What’s the scoop?