Hello everyone i just picked up a used unit and i am trying to figure out the best way to vent the unit in my masonary chimney. I have a piece of stainless flex piping that came with it. I am curious about what to use for the fresh air and also how to connect the flex tubing to the unit. I have a tee that came with it also but it does not attach to the flex pipe with what i have. What should i use? Thanks guys