I finally got around to having the inspection on the york modulating furnace i had replaced upstairs. It failed inspection. Obviously i alerted the installer, who has a good reputation and i'm pretty sure will take care of it. Can someone explain the failure: "install overflow protection on safety pan since primary and secondary drains are tied together". The system drains by pvc pipe to a large pvc pipe that i think is the sewer pipe? Is there a "easy fix" and a "perfect" fix?