Some chimney guys who do video scans will "fail' the liner if the joints aren't fully mortared. I see that exact situation frequently. I tell them exactly what Kurt said, and advise that a chimney pro can decide what the best course of action is. Bill, the pitting seems to be very minor on the surface. chimney guys I know wouldn't even blink at that amount of wear. John, did you take a cap off to check the liner? Several HI's have told me not to take the cover off- liability, etc., but there's a lot of good stuff to see by taking them off.