Sue,
The controller is factory-set to a high-temp alarm at 290. Press and hold the SET button until Lck appears in the left window. Then, put 155 in the right window (+/- buttons). Each time you press SET, the next program parameter will appear. You are looking for AH1. When you land on it, put 375 in the right window, and press SET again. I would also recommend setting the AH2 (probe 2) high limit to 210, not the factory preset of 200.