I just received my FEC100 on Friday and decided to do 2 test runs this weekend to see how it holds temp. First test on Saturday was set at 225 but was getting oven temps of 300-325 constantly.. Second test yesterday, I had set at 180 and was hanging around 225 but would occasionally go down to around 175-185 for a brief amount of time. I'm sorry I'm no help but I am curious to hear what customer service says when you call.