So I was looking at putting a wood insert in my ZC fireplace but due to safety concerns changed my mind. My question is I found a Quad Casitle pellet insert for sale for a good deal and it includes a 4" liner. I looked up the Quad manual and see the ZC notes but I'm still not clear on the liner part of things. First off do most consider this a safe and tested install? Second, do I need a insulted liner? or is recommended? Any input would be great. I want to move on this before its gone.