I'm new at this pellet stove stuff and the other day I posted some info on installing an adjustable vent pipe...it's a Duravent pellet pipe NOT the Pro-Pipe...anyways a fellow member mentioned that I might have installed this upside down...?????...I'm having trouble trying to find some info on the installation of these pipes....see pic below......HELP........my finger is pointing to the sliding open end of the pipe...which is on the stove side of the pipe..