I've had an Enviro Mini for many years, and have serviced most things on it, at one time or another. Currently, I'm redoing the roof, and I plan to reroute the 3" chimney on the pellet stove. My question is, how much clearance is required around the chimney where it passes thru the roof? I was told 2" of clearance by a local wood stove shop, but I can't seem to find such info on the Enviro website or any other reliable source online. I see some thru-wall thimbles, that seem to only have a 6" opening for a 3" pipe. Obviously, I don't want to create a fire hazard, but I would like to have a smaller hole in the roof, and to reduce heat loss.