I am a total newby at smoking (in face I haven't smoked anything yet). I just got a new Brinkmann Smoke N' Grill 5-Burner Propane Gas Grill with Smoker for Father's day and decided to burn it in this morning. Read the instructions (almost none) put in some apple chips (what I had) lit it up on high and let it go for about an hour (OK I forgot about it). When I came back I noticed that the temperature was only about 300 degrees. When I looked around the grill I noticed that the Smoker box has a flue coming out of the top back of the box that is about 4 inches by 4 inches and wide open with no way to close it off. My question is this. Do propane smokers usually have adjustable flues like the charcoal units I've seen or are all of them wide open like this one?