Do any of you folks know what the heck the difference is between the PVL and PVP pipe is and will they interchange. I know I must have a mix because when I installed a few years back I just ran straight out the back and then last year I added on and went up vertical 7' to add some draft. It seemed some of it did not want to go together without a fight and I am assuming that was because of the difference between the PVL and PVP. I know the PVP is the Pro but not sure what the other one is. Thanks for the help
