Fireplace is a ambiance elegance 40 by supreme. Currently, the longest burn I’ve gotten is 6 hours. Average is about 3-4. Very rarely more than that. That’s from load up to a point where my coals are cool enough to barely start a fresh log. Wood is dry and seasoned below 20. Splits have been relatively small ( about the size you would get if you bought from a home store). I thought that might be the issue so I got some fat logs from a friend that were about 7-8”splits 2 yr seasoned oak. Firebox is 3.2 cubic ft so I can fit about 3-4 in there. I nest them in tight East to west. It burns fairly slow to start but seems to be engulfed and raging after about an hour. Cutting air control as much as I can doesn’t slow it down much until about nearly hour 2. After hours 3 I’m down to chunky coals. Stove claims 6-12 hr burn times. There is no way. I think I’ve tried everything. Am I missing something?