Hey, I have a new jotul f3 and simply love the stove. Burns great and heats wonderfully. I have only one problem. It seems that if I add more than one piece of dry red oak or loqust the stove quickly goes to 700 degrees or hotter with no control. Of course I completly shut off the air before loading. Im vented vertically out the back of the stove with a tee about 14 feet high with Dura vent pipe. Wondering if I should consider a damper. Right now burn times are short because I can only load one piece at a time to prevent over fire. Any one else had any experience????