Hello, We had a wood stove insert in an existing fireplace. This fireplace had a brick chimney that was falling away frm the house so was replaced with a class A 6" stovepipe with a wood chase built around it about 5 years ago. (chimney was on exterior wall) Worked great for the wood stove set up. We've decided to switch from wood to gas. Main reasons are we need a faster source of heat for the room and less work involved now that we have kids and a busier schedule. I sold the insert a few weeks ago and now are on to selection agas unit. The problem we're running into is we're told the 6" stove pipe is not big enough to run the 2 3" vents for direct vent gas stove. The local fireplace store had no other options for us as they only sell direct venting units. I have been told a B vent may work but also know they are not as efficient. Does anyone have a recommendation? We are open to having a gas stove on the hearth instead of an insert. I don't want to pull out the stove pipe or chase but find something that works using it. It was expensive to have installed/repaired so we'd like to salvage it for the gas venting. Plus a future homeowner would have the option of converting back to wood if they so chose. Open to suggestions. thanks!