I live in York Region (Vaughan Ontario). The gas company came by and performed a visual inspection. They identified my furnace exhaust pipe (black APS 2") is starting to crack at the coupling (its about 2 feet above the actual furnace) and said I should replace the pipe with the white PVC (Ipex or Royal).
I did some research and based on the recommendation, I should prime, then glue the new pipe.
I'm assuming I can cut the black pipe with enough room to add a coupling just above where the pipe comes out of the furnace and then continue with the new white pipe.
Can I also add a coupling at the other end near the exterior wall of the house? Do I have to replace the full length to the white pipe to make it go outdoors? Obviously its easier to just add a coupling near the wall since the exterior is all caulked and already sealed. In essence I would have about 2 inches of black pipe coming out of the furnace, then about 8 feet of white pipe, another coupling joined to about 1 foot of black pipe which is already going out doors.