I've decided on a BlazeKing Princess for the new home I'm building. I want to use the Outside Air Kit but have a few questions: 1. I'm building on a concrete slab so I have to add the vent under the slab before pouring the concrete. Can I just use 3" drain pipe? 2. How long can the vent pipe be? 3. Can the vent pipe run up the wall into the attic to draw air? Any other suggestions would be appreciated.