Arrvied onsite per customer request of getting his furnace looked at. Upon arrival I found the furnace to not be operating correctly. Offered customer pricing for a replacement as well as a diagnostic. Customer elected to do a diagnostic so I began. Upon going through my diagnostic I found the flame inside pilot to ignite but would not stay lit. Got on the phone with tech support and had a conversation. Tech Support Conversation: Got on the phone and spoke with a man named Ted, Ted walked me through the possible secenarios for the reason I was getting a measurement that was bouncing between 1.1UA and 1.6UA when testing my flame sensor. He left me know that the issue I’m most likely having is with my venting(roof jack). So that is where I started, disconnected the cap on top of the roof and found the venting to be corroded. Took apart both 45 degree offsets on top of the furnace and found them to be corroded and leaking. After reading through the manual we discovered the way the u