My grill + smoker combo (Kenmore, from Sears) works great.. EXCEPT that I can't keep the temperature in the smoker below 275 degrees! I turned the temp control down to "LO", but the thermometer won't register anything lower than 275 unless I open the front door for a bit... and once I close the door again, the temp climbs straight up to 275. A quick review of posts shows that lots of folks have trouble keeping the temp UP. Am Ithe only one having the opposite problem?