hey guy's , I will be on vacation in about two weeks and plan on installing my class a chimmey system. I purchased a super vent thur -the- wall- kit, I was going over the instructions and getting a general idea how everything should go, but there is one thing i quite don't understand. When you cut your hole out for the thimble and place the prefab thimble in the hole how far must the class a pipe extend into the room, I was reading my instructions and if i understand it right it was saying that the pipe should extend 3inches into the room, does this sound right? I 'am worried it will look funny having a three inches of stainless pipe connected to my black stove pipe. help me out guy's maybe there is something i don't understand here.