was at this house yesterday to work on the AC when i saw this in the basement, it was installed the day before. Power vented water heater was replaced with a natural draft water heater. This is not a homeowner install, this was done by a contractor, homeowner was not aware of any problems. Not going to comment on the pics myself, would like to hear some unbiased opinions from other techs.
water heater, note abandoned 2" pvc vent pipe:
pipe exits the side wall:
termination, new is between line set and disconnect, old abandoned vent is off to the left