- Oct 3, 2007
- 1,539
I just got my permit approved for the installation of my 28-3500 add-on furnace plus the chimney. I was going to use an offset to route the chimney around a 1st floor window (the furnace will be in the basement), but I'm now seeing in the Hart and Cooley installation guide that elbows may not be used outdoors. Anyone know why? What do I do now?