Over time, your oven's thermostat may lose accuracy. If this happens, the temperature inside the oven will not match the setting on the control panel and your food will come out undercooked or burnt. Fortunately, you can recalibrate the thermostat on most ovens in less than a half hour. You will need a simple oven thermometer so you can find out the actual temperature inside the oven.
Turn on the "Bake" mode and set the temperature dial to 176 degrees C. Press "Start" and wait for the oven to preheat. Open the door and set an oven thermometer on the centre baking rack. Close the door and wait 20 to 30 minutes.
Put on an oven glove to protect your hand and take the thermometer out of the oven. Recalibrate the oven's thermostat if the reading on the thermometer is more than -12.2 degrees C over or under 176 degrees C. If the difference is greater than 1.67 degrees C, the thermostat is probably defective and cannot be fixed through a simple recalibration.
Consult the owner's manual to find out how to recalibrate your oven's thermostat. If your oven has an electronic display, the exact procedure will vary by oven, but it is generally done by pressing the up and down arrows until you reach the desired setting.
If your oven does not have a display screen, pull off the temperature setting knob. The calibration dial will either be under the knob or in the shaft. If the dial is inside the shaft, insert a small flathead screwdriver to turn it clockwise and increase the temperature or counterclockwise to decrease the temperature. If the dial is under the knob, loosen the retaining clip and adjust the dial by hand. Replace the retaining clip to lock the dial in place.
Replace the temperature knob and repeat Steps 1 and 2 to test the thermostat again. Continue adjusting the calibration dial and the thermostat until the reading on the oven thermometer matches the setting on the dial.