The Power Direct Vent is designed with a sealed combustion chamber, ultra quiet blower and state-of-the-art Robertshaw® gas control for highly accurate temperature control. The Flamable Vapour Ignition Resistant (FVIR) design prevents flammable vapours from entering and igniting. All combustion air is brought in from outside - rather than heated air from indoors. The Power Direct Vent can be vented with 3" ABS, PVC or CPVC up to 60' horizontally through the wall or vertically through the roof.