Can someone tell me if the, flap, air regulator in the back of this stove is temperature regulated? I swear that after I close the top damper and front doors and reach my second (horozontial) burn, the flap will sometimes close. The little metal handle is still where I placed it but I am sure the flap has closed a little. If it is temp. controled do I set the flap where I want it and the flap will open or close to allow more or less air in?