proq Frontier air leaks

I just received my new Frontier a week ago, and have done 2 smokes on it. I am having a problem keeping the temp down, even with all the lower vents are 100% closed. ( I do leave the top 100% open) . I have been using the Minion Method to start my fire, I have been using a full basket of charcoal briskets, and a half a starter chimney for light coals, and the water at 3/4 full. Doing this I have a hard time keeping the temp below 250-275. I believe I have a lot of air leaks that even with the lower 3 vents 100% closed there is a lot of air getting in. When I am done cooking, and close off all the vents, including the top one, it will still maintain a temp of 250 till all the coal is spent.

I get a lot of smoke coming out around the doors and where the sections come together. The stacker sections seem to be round and not bent, and they go together good. So not sure what to do at this point.

Forgot to add that I Calibrated the temp gage using boiling water, and checked the temps using two different digital thermometers, at different sections, the temps were within 5 deg of each other.
Thx
Bubba

Try and catch the temps on the way up. When the cooker hits about 190 place you food on and replace the lid quickly.

If you let it get to 225 then open and load the air will enrich the fuel and cause to much of it to start burning thus too high a temp range.