This will be my third year running a Clydesdale insert. I have a 1600sf ranch, and 12' of insulated flue. The top temp. never gets past 500 degrees. My wood is mostly 1 year css locust and ash. Is it possible I should add to the flue? Or are these temps. normal? Even when burning old oak pallets the temps don't climb. It's heating my home, but I'm wondering if I'm not burning efficiently. Thanks Ken