I'm looking at switching to Selkirk Direct-Temp whenever the need to replace my Bixby Maxfire (3" inner pipe; 5" outer pipe) arises. Currently, I have a basement install with a 9' vertical rise and a 2 foot horizontal termination. In order to prevent soot-buildup on my outside brick, I had to extend the 3" center exhaust pipe a few feet. Does anyone have a horizontal termination using Direct-Temp and if so, do you have any issues with soot buildup on your outside wall? If not, how far away from your wall is the termination? If so, what have you done to prevent the buildup? Thank you?