What is the acceptable temperature of the exterior pipe on b-vent exhaust.
I have a 100k btu Lennox furnace with about 6 feet of b-vent connecting to a c-vent "Y" with my water heater and continuing horizontally about 10 feet before going vertical about 15-20 feet through the roof.
I ask because the a/c pvc drain is near, 1.5 inches away, the exhaust and shows signs of scorching. It has happened over a long period of time, but I just now noticed it.
Should we just replace the scorched pvc and not worry. The temp of the b-vent with the furnace running is about 148*F, done with a k-type probe on my multi-meter.