I noticed when I was on the roof that the cap on this pipe located next to the A/C unit had crumbled. I temporarily duct taped it tight but was wonder if it needs to vent.
I'd buy a new cap.. The only vents I've seen on the roof are for the black and grey tanks... Without the caps, rain can get to the roof and leak down the stack, depending on how well it is sealed when it comes through the roof..