A couple months ago I bought a new MES40 because I really liked my old MES30, but wanted a bigger unit. I've used it twice since "seasoning" it and for the most part it has been great.
Making a batch of summer sausage this weekend, I noticed a couple things that didn't occur last time I used it. First, the internal temp of the smoker is about 15 degrees cooler than the thermostat in the unit says its at. The first couple times I used it the built in thermostat was about 5 degrees cooler than the actual temp in the box. Second, I found there were really big temp swings going on. For example, if I set the temperature to say 140 degrees the heating unit/thermostat will let the internal temp drop 5 to 10 degrees before the heating element kicks in. Then, it jumps up to 10 degrees or more above the setting. My old MES30 would kick on the heating element if the internal box temp dropped a degree or two below the setting and just stay on briefly to keep a pretty constant temperature in the smoker.
I'm not sure if I have a problem with the thermostat or if there is a sensor probe problem. Any ideas?