My fireplace has an ash dump in the floor that I would like to utilize to making cleaning the chimney easier. What I am thinking is that I will run a piece of liner from the bottom of the TEE into the ash dump. The ash dump is about 7 or 8 feet deep and can be accessed from a cleanout on an outside wall of the basement. Are there any requirements for the piece of liner that I run from the bottom of the TEE into the ash dump? I imagine the liner running from the TEE into the ash dump has to be capped at the end, or can I just leave it open? It would be easier to leave it open at the end...that way I could just run the liner down into the top part of the ash dump without having to go the entire 6-7 feet. Something doesn't seem right about leaving it open at the end, however....