I am trying to figure out if double wall pipe will fit in this support box that I have or if it was installed incorrectly. Everything I’ve seen while searching shows double wall pipe has black exterior with a stainless interior. The stainless chimney in my installed ceiling box does not come down far enough to be able to attach pipe, unless there is some kind of adapter or pipe where the stainless inner section protrudes out farther than the black exterior section. This is a Security exterior chimney system.