Have a full masonry fp that is used only few times per year. Decided to put VC Direct vent gas stove on hearth and vent up chimney. Installer just here and said damper throat too small to fit 7" double wall without cutting it, then can't go back to wood FP. He said the b vent would be fine and I wouldn't like the looks of the two pipe system going up chimney. Why would I want to use house air when system can be closed DV?? Isn't that alot less efficient?

INstaller also says he just runs 6" pipe up to new cap and stuffs insulation around pipe at damper? I envisioned a metal plate with a hole cut in for pipe? Should I find a new installer?

Thanks for all advice, need to get this done b4 christmas or I'm in the doghouse. TKS.