Why doesn't it heat to set temperature?
Hello. In most ovens with an electronic control, the temperature is regulated by 2 things--the sensor and the oven control board. The sensor is simply an electrically resistive device that changes resistance as the temperature increases or decreases. It is connected to the main control board by 2 wires(just a "pigtail") and the main board is supposed to be calibrated to adjust properly. Most control boards have a built-in program by which you can adjust the calibration +/- 35 degrees. If your oven is outside that range, and you're sure that the sensor is good, the connections are good, etc., then the oven control board temp control circuit has gone bad. Keep in mind, when you turn on an electronically controlled oven, the first time it heats up is USUALLY hotter by about 50 degrees--this allows the floor, walls, and ceiling to reach proper temperature. This is called the initial spike. In gas ovens, the user must wait approximately 8-10 minutes AFTER the oven beeps to cook anything. In an exposed-element electric oven, the user waits approximately 10-15 minutes after the beep. In the hidden bake element models, waiting 20-25 minutes after the beep is normal!
Also, keep in mind, ovens can have 60 degree temp swings higher and lower(as long as the midpoint is close to the chosen temp) I hope I've helped you!