How to Calibrate an Oven
When you move to a furnished apartment or when you buy a new electric range, more often than not you’ll tend to compare the newly acquired oven to your previous one, and being familiar with that one, you most likely learned with time to add or subtract to your recipes’ baking temperatures. The truth is that not all ovens are created equal.
Oven controls are set when installed at the factory. Brand new appliances, when compared, can heat at noticeable temperature variations, so when you follow the recipe and set your oven at 350°F (180°C) to bake a cake or cookies, and your oven only reaches 320°F (160°C) at its center, your baking goods will take longer to brown.
But if it happens to run hotter at 370°F (188°C) or 380°F (194°C), you’re going to find that your cakes will dome, and your cookies will brown on the outside while your baking goods remain under-cooked on the inside. The good news is that you can correct this by calibrating your oven’s temperature.
How Oven Calibration Works
Using the touchpad or the knob on the control panel, you manually set the temperature of the oven by inserting the three digits on the ERC (Electronic Range Control) screen on the front of the appliance, or by turning the oven control knob clockwise to the right temperature marking on the dial. That set temperature is then monitored from inside the oven box, so the thermostat or the ERC knows when to shut it off or turn it back on.
You should know that an element always runs at full power when voltage is applied to it. So how to control it is simply a matter of running hot until the oven cavity reaches a temperature slightly higher than programmed or set, then shutting it off until it cools down to a lower than set temperature. So this means you work with an “average” temperature that keeps fluctuating slightly up and down.
Step 1 - Compare the Actual Oven Temperature with Its Setting
To recalibrate the oven, you need to find out exactly how bad the temperature variance currently is. This can be figured out with only the use of an oven thermometer from which the temperature variance obtained will be as accurate as the thermometer’s accuracy.
Since many oven thermometers commonly sold in grocery stores are actually off by 20°F (11°C) or more, you should look for a more dependable and proven model, such as the KT Thermo or the Taylor 3506 TruTemp thermometer.
1.1 - Open the oven and check the temperature sensor at the top of the back wall, usually on the left side. Make sure the sensor is properly secured in place on the back wall and not touching any other parts of the oven.
1.2 - Place one of the grates at the halfway height of the oven chamber.
1.3 - Place or hang your thermometer in the center of the oven chamber and close the door. The door must be kept closed until your get the final temperature reading.
1.4 - Preheat the oven to 350°F (177°C). Allow the oven to heat for at least 20 minutes, then take a temperature reading.
1.5 - Keep taking readings every 20 minutes for about two hours or no less than four readings.
1.6 - You can now calculate the average temperature from all your readings by adding them together and dividing the total by the number of readings taken. The result should be around the same value as your oven setting, which should yield a variance of less than 10°F ( 6°C) either way, which means that anywhere from 340° to 360°F (171°C - 182°C) could be acceptable.
If your calculations tell you that your oven is heating at 365°F when set at 350°, you should readjust the calibration offset by minus 15° (-15°) as in Figure 5 in order to lower that actual temperature down. The same goes if the calculations reveal instead an actual temperature of 335°F. Your calibration offset will then have to be 15° (Fig. 4) to bring it up to the set level of 350°F.
Warning—The variance between the low and the high peaks can sometimes be quite large, and if your oven happens to reach excessively high variances such as 100°F (38°C) or more, you will likely be facing other problems such as a defective temperature sensor or a faulty thermostat, and you might have to reach out to a certified technician for a more accurate assessment.
Step 2 - Adjusting an Oven with Analog Control
If your oven is controlled by dialing a knob on the front panel, your calibration process will be done from mechanical adjustments on the thermostat, the knob, or the post of the rotary control.
2.1 - Remove the oven temperature knob from its post by pulling it out. If there is too much resistance, just pry it gently out using a butter knife or a flat blade screwdriver.
2.2 - Turn the knob over and look at it. If there is a notched disk and a pointer in the back of it, these will be your marks and guides to calibrate your oven. If it’s not there, it could be mounted on the thermostat control, as this is the most common method used to adjust analog controls. Each of the markings on the disk normally represents a 10°F (6°C) temperature shift.
Other methods of adjustments are used, however, which will require you to consult your owner’s manual and follow its specific instructions for that oven model.
2.3 - Make a mark on the disk to remain in perspective with the original setting.
Note: If, before attempting any adjustment, the disk is on the zero mark or the screw is centered within its slot, it’s very likely that it is still at the factory default setting.
2.4 - Loosen the screws holding the disk in place.
2.5 - Rotate the disk slightly within the limit of its slotted adjustment, guiding yourself with the 10° marks. Rotating one way will increase the temperature setting while turning in the opposite direction will decrease it.
2.6 - Tighten the screws back up to secure the disk in place and return the knob onto its post.
2.7 - You can now repeat steps 1.1 to 1.6 to verify what the new actual temperature of the oven is. If it is still outside the 10° F (6°C) acceptable margin, you might have to repeat steps 2.1 to 2.6 until it is right.
n the extreme case where it cannot be calibrated, or your temperature variance is too great to be calibrated, you could be dealing with a faulty thermostat or other component and might have to consult a certified technician for advice.
Step 3 - Adjusting the Oven Temperature from a Touchpad.
3.1 - Since there are so many different manufacturers and models of appliances, each one with its own procedures to calibrate the oven, the one thing you will probably need to calibrate the oven temperature is the owner’s manual listing the specific instructions on how to do it.
If you don’t have a hard copy of your owner’s manual or user guide, look it up online and go to the section about oven calibration or about “adjusting oven temperature”.
The instructions on how to adjust the oven temperature will specify which button(s) you need to press to activate the process and for how long, and also the time-lapse (in seconds) that you have to confirm the setting and return the touchpad to its normal screen.
If your touchpad has numeric buttons instead of the “arrow up” and “arrow down” buttons for value selection, the manual will provide you with the proper sequence to make your selection into a positive or negative temperature value since the touchpad doesn’t actually have a minus (-) or a plus (+) button.
The procedure used here is based on the Kenmore C970 wall oven, which works with the less commonly described numeric touchpad instead of the buttons with arrows (Figure 1).
3.2 - For most models, you can initiate the calibration process by pressing two buttons simultaneously for between two and fifteen seconds, or as in this example with the Kenmore C970, pressing the “Bake” button and setting the temperature to 550°F (287°C) as in Figure 2, then pressing “Bake” again within two seconds.
A double digits display, as shown in Figure 3, will appear on the readout to confirm that you’re in the calibration mode. Some models will require you to press two designated buttons, such as the “Bake” plus another, such as the “Oven light” or the “Timer” button, holding both between two and fifteen seconds.
You’ll need to refer to your manual to get the proper sequence or procedure to activate the calibration mode for your particular oven.
3.3 - The double-digit number now shown on the display in Figure 3 shows the actual offset of your oven temperature setting. If the number is “00”, your oven is probably still at its factory setting.
On different models, you might get instead a reset message such as “SF,” “F TempOffset,” “0 F CAL”, or 00.”. Just follow the procedure from the manual.
3.4 - From your oven temperature testing result obtained earlier, use the numeric touchpad or the “arrow up” or “arrow down” to enter the difference in temperature between the actual oven temperature and the factory set temperature.
The oven temperature offset on this Kenmore example may be increased by as much as +35°F (+19°C) or decreased by -35°F (-19°C).
3.5 - Skip this step if you’re adjusting using the arrow buttons. If you’re adjusting using a numeric touchpad, however, being what it is, it will only let you enter a numeric value without specifying if it’s to be an increase or a decrease in value.
So for the Kenmore oven with a numeric touchpad, you’ll need to add another step by pressing the “Flex Clean” button (Figure 4) in order to add a plus or a minus sign in front of your set number.
As shown in Figure 5, touching “Flex Clean” will add or remove the minus sign in front of the 15°.
For any other model, you’ll need to consult your owner’s manual and find the proper procedure.
3.6 - To finalize the calibration on the Kenmore C970, your selection now needs to be confirmed by pressing the “Bake” button again. With any other oven model, you’ll need to follow the specific instructions as described in its manual in order to confirm your selection.
3.7 - The calibration can now be tested by going through steps 1.1 to 1.6 to confirm that the actual temperature of your oven is now within an acceptable range.
If, however, the calibration did not correct the issue, you might consider the possibility that the problem might be caused by a faulty heating element, thermostat sensor, or other components. And as mentioned previously, you should call upon a qualified professional if the temperature is off by more than 100˚F (37.78˚C).
Calibrating a Gas Oven
You should only attempt to calibrate a gas oven that has digital controls. The calibration in this case would be done in a similar manner as described previously for the touchpad oven controls. If it has a control that is adjustable from a knob on the control panel, however, the process is much more complicated and risky and should only be done by a certified technician.