I have an older (un-used) pellet stove that I would like to install. I have been shopping for all of the vent pipe to get it installed, then realized the vent outlet on the back of the stove is 2", and all of the adapters online are 3" at the smallest. Is there a way that I can safely adapt this 2" vent outlet to meet the 3" standard? I cannot seem to find an adapter from 2" to 3" anywhere.