I once had a T5 and then I moved and got the T6. Something that I noticed is different is the air control lever. In the T5 it was attached to a rod that went to the rear underside of the stove and moved something back there to let air in or restrict the air. In the T6 the lever doesn't have the rod. It only covers a circular hole toward the front underside of the stove. The hole it about an inch or two in diameter. At the rear underside there is a metal box with a square hole with a flap that clicks when I open and close the main door on the stove. There is also a metal cover with six holes on the bottom lip inside the stove. Is this the only source of air intake for the stove? If so, what if ashes get high and cover the holes? Can anyone with experience tell me what is going on with the T6? Where does the air come into the stove? What is the box with the flap that clicks when I close the door? Sometimes I with there were more air to put into the stove to get the fire going better. Sometimes I have to leave the door cracked open to get the wood to catch fire. Part of that could be the wood that isn't as seasoned as it should be. I was also wondering how common is it for the stove to let smoke out into the room when the door is opened. I've been noticing that it does it every time the door is opened. This is my second season to use the stove. My stove pipe is probably about 15 to 20 feet tall and goes straight up, except for a notch to get it past a rafter in the roof. Thanks for your help.