Yes, even if I don't try to calibrate it, it keeps heating up past the set temperature. It only flipped the breaker once when I tried to calibrate it the first time. I haven't let it get that high again without shutting it off. It set my smoke alarm off so I was a little worried to let it keep heating up and of course it's a weekend without customer service! Is it normal for it to heat up that high during calibration?