Had my medium egg since just before Xmas and have done a lot of food on it, including several racks of ribs.
Never had a problem with temp control until yesterday, lit in my usual way with electric starter, left open until burning clear, added place setter and started closing own bottom vent. At 200 added DW and closed down bottom vent more, after 30 mins temp was 240 closed down to my usual slow cook settings and added ribs.
Temp kept rising slowly so I shut down till there was virtually no opening and closed DW till there was only about an 1/8th of an inch gap on the daisy.
Still the Temp kept rising slowly and it was at 350 after 3 hours, had to take the ribs off. They tasted good but were dry compared to my norm because of the higher temps.
Don't know what was going on but I could not keep th temp from rising, I couldn't shut the vents anymore or it would have gone out.
Checked the egg this morning and it had burned more than twice as much lump as normal for ribs.