I have been burning my Napoleon 1402 Insert for a couple weeks now and I noticed it seems like my wood burns up pretty quick. I am not seeing the burn times I anticipated. I have a 22' run of 6" SS Flex liner with an insulated block off plate. When I get things burning good and hot and I shut down the primary air all the way I still have solid, aggressive flames and monster Secondary combustion. I would have expected the flame to die down and get much lazier? Is it possible my draft is just to strong? I have done quite a bit of research on here and it seems overdraft with an insert doesn't have a lot of options?