Thermostat calibration? How do I calibrate the oven thermostat?

The thermostat is mechanical using pressure from a waxstat style sender and is not adjustable.
I expect you are measuring with your probe in a different place to the sender unit; hence the differences.

ADJUST OVEN FLAME LEVEL: Normally, thermostats are calibrated by pulling the oven's thermostat knob off, turning the knob over and adjusting the calibration ring on the back. If your oven doesn't have a calibration ring you may need to replace the thermostat. The reason for my free advice is GOD is good!

Sometimes the oven thermostat or oven sensor can be calibrated wrong, or it may be faulty. If your particular range has an oven that uses an electronic thermostat, and the oven temperature is off by tens of degrees, you probably have to replace it.
On most units that have a mechanical thermostat, you can actually remove the thermostat knob, and adjust the knob to more accurately represent the actual setting of the thermostat. On many models, there's a screw on the back of the knob with a small calibration plate or ring. You can loosen this screw and adjust the calibration plate. Remember to tighten the screw again. If yours isn't adjustable, and the temperature is off by a large amount, you should just replace the thermostat.

Or Oven safety valve needs to be checked with multi meter ohms / voltage

ALSO Test the Burner Heating Element

Most of the time, whn this problem occurs on ovens, it is mainly caused by the ovens thermostat. Run a test on the oven thermostat and replace it if it is faulty.
An oven thermostat is a switch that opens and closes in response to the temperature it senses. It is typically found in the control panel, where a liquid-filled temperature-sensing bulb senses and maintains the internal oven temperature by cycling heat on and off.
Before repairs or testing can begin you must disconnect the electricity at the fuse panel, at the circuit breaker panel, or by pulling the plug. Make sure the power is off before proceeding. A jolt from 220 volts can be fatal, use caution!
Access the oven thermostat, which is located in different places depending on the make and model: On freestanding ranges, access the thermostat by removing the screws that hold the back panel in place at both ends. On models with front-loading controls, remove the panel and tilt it for access. Be careful not to let the wires disconnect from their components. Some built-in models have a removable backsplash. Lift the backsplash, rest it on the cook top and remove the screws from the backsplash, which holds the rear panel. On wall ovens or eye-level ranges, access the control panel by opening the door and removing the screws that secure it. The screws may be under the exhaust hood or below the control panel. If the control panel is hinged, simply tilt it towards you. On some models both the rear and front control panels must be removed. The screws may be found on the trim and occasionally the trim must be removed.
When testing the thermostat switch contacts for continuity, refer to the wiring diagram and remove only those wires being tested - and only one pair at a time. Test switch contact terminals as per your wiring diagram. If the switch lacks continuity at any of the contact terminal points then the entire thermostat switch needs to be replaced.
Adjusting the thermostat: Test the oven temperature by placing the tester in the oven's center and leaving it for 30 minutes at 350 degrees. Record the minimum and maximum temperatures of three cycles, then add those figures together, divide the result by six and you have the oven's average temperature.
If the average temperature is more than 25 degrees off, try calibrating the thermostat by following your appliance manual instructions for thermostat calibration.
Normally, thermostats are calibrated by pulling the oven's thermostat knob off, turning the knob over and adjusting the calibration ring on the back. If your oven doesn't have a calibration ring you may need to replace the thermostat.
To remove the thermostat: Disconnect the capillary tube and push it through the back oven wall, being careful not to break the flammable capillary tube wire. Remove the screws that secure the thermostat to the control panel and gently pull the thermostat out, leaving the wires in place. To install a new thermostat, reverse the disassembly procedures, transferring the wires individually from the old unit to the new.
Hope this was helpful. Thanks for using fixya.

An oven thermostat is a switch that opens and closes in response to the temperature it senses. It is typically found in the control panel, where a liquid-filled temperature-sensing bulb senses and maintains the internal oven temperature by cycling heat on and off.
Before repairs or testing can begin you must disconnect the electricity at the fuse panel, at the circuit breaker panel, or by pulling the plug. Make sure the power is off before proceeding. A jolt from 220 volts can be fatal, use caution!

1. Access the oven thermostat, which is located in different places depending on the make and model: On freestanding ranges, access the thermostat by removing the screws that hold the back panel in place at both ends.On models with front-loading controls, remove the panel and tilt it for access. Be careful not to let the wires disconnect from their components. Some built-in models have a removable back splash. Lift the backsplash, rest it on the cook top and remove the screws from the back splash, which holds the rear panel. On wall ovens or eye-level ranges, access the control panel by opening the door and removing the screws that secure it. The screws may be under the exhaust hood or below the control panel. If the control panel is hinged, simply tilt it towards you. On some models both the rear and front control panels must be removed. The screws may be found on the trim and occasionally the trim must be removed.
2. When testing the thermostat switch contacts for continuity, refer to the wiring diagram and remove only those wires being tested - and only one pair at a time. Test switch contact terminals as per your wiring diagram. If the switch lacks continuity at any of the contact terminal points then the entire thermostat switch needs to be replaced.
3. Adjusting the thermostat: Test the oven temperature by placing the tester in the oven's center and leaving it for 30 minutes at 350 degrees. Record the minimum and maximum temperatures of three cycles, then add those figures together, divide the result by six and you have the oven's average temperature. If the average temperature is more than 25 degrees off, try calibrating the thermostat by following your appliance manual instructions for thermostat calibration. Normally, thermostats are calibrated by pulling the oven's thermostat knob off, turning the knob over and adjusting the calibration ring on the back. If your oven doesn't have a calibration ring you may need to replace the thermostat.
4. To remove the thermostat: Disconnect the capillary tube and push it through the back oven wall, being careful not to break the flammable capillary tube wire.
5. Remove the screws that secure the thermostat to the control panel and gently pull the thermostat out, leaving the wires in place.
6. To install a new thermostat, reverse the disassembly procedure, transferring the wires individually from the old unit to the new.

Hope this was helpful.Thanks for using fixya.

You need to check the oven cycle relay,

1. Before repairs or testing can begin you must disconnect the electricity at the fuse panel, at the circuit breaker panel, or by pulling the plug. Make sure the power is off before proceeding. A jolt from 220 volts can be fatal, use caution!
2. In order to gain access to the oven cycling relay, refer to your owner's manual. Removing the back panel of the range accesses most relays, but some ranges locate the relay under the oven compartment where the utility drawer is usually located.
3. Now you can test the relay using your VOM. First, label each wire attached to the relay and remove them from the relay terminals. Using your VOM's ohmmeter function, set the range to R x 1 and touch one test lead to the terminal marked L and the other test lead to terminal H2. There should be NO continuity. Next, test the terminals marked H1 and H2. Again, there should be NO continuity. Finally, test the S and R terminals. Continuity should exist between these two terminals. If your relay does not pass all these tests, it is defective and should be replaced.
4. To remove the relay, undo the two screws securing it to the range and replace with the correct new relay. Refer to your wiring diagram and labeled wires to ensure that the wires are on the correct terminals. Now replace the back panel or drawer and test the oven.

Then you check the oven thermostat: When testing the thermostat switch contacts for continuity, refer to the wiring diagram and remove only those wires being tested - and only one pair at a time. Test switch contact terminals as per your wiring diagram. If the switch lacks continuity at any of the contact terminal points then the entire thermostat switch needs to be replaced. Adjusting the thermostat: Test the oven temperature by placing the tester in the oven's center and leaving it for 30 minutes at 350 degrees. Record the minimum and maximum temperatures of three cycles, then add those figures together, divide the result by six and you have the oven's average temperature.
If the average temperature is more than 25 degrees off, try calibrating the thermostat by following your appliance manual instructions for thermostat calibration.
Normally, thermostats are calibrated by pulling the oven's thermostat knob off, turning the knob over and adjusting the calibration ring on the back. If your oven doesn't have a calibration ring you may need to replace the thermostat.
To remove the thermostat: Disconnect the capillary tube and push it through the back oven wall, being careful not to break the flammable capillary tube wire. Remove the screws that secure the thermostat to the control panel and gently pull the thermostat out, leaving the wires in place. To install a new thermostat, reverse the disassembly procedures (Step 7 above), transferring the wires individually from the old unit to the new.
Hope this information helped you.

Hello there:

An oven thermostat is a switch that opens and closes in response to the temperature it senses. It is typically found in the control panel, where a liquid-filled temperature-sensing bulb senses and maintains the internal oven temperature by cycling heat on and off.

1. Before repairs or testing can begin you must disconnect the electricity at the fuse panel, at the circuit breaker panel, or by pulling the plug. Make sure the power is off before proceeding. A jolt from 220 volts can be fatal, use caution!



2. Access the oven thermostat, which is located in different places depending on the make and model:
   1. On freestanding ranges, access the thermostat by removing the screws that hold the back panel in place at both ends.
   2. On models with front-loading controls, remove the panel and tilt it for access. Be careful not to let the wires disconnect from their components.
   3. Some built-in models have a removable backsplash. Lift the backsplash, rest it on the cook top and remove the screws from the backsplash, which holds the rear panel.
   4. On wall ovens or eye-level ranges, access the control panel by opening the door and removing the screws that secure it. The screws may be under the exhaust hood or below the control panel. If the control panel is hinged, simply tilt it towards you.
   5. On some models both the rear and front control panels must be removed. The screws may be found on the trim and occasionally the trim must be removed.
   
   
   
3. When testing the thermostat switch contacts for continuity, refer to the wiring diagram and remove only those wires being tested - and only one pair at a time. Test switch contact terminals as per your wiring diagram. If the switch lacks continuity at any of the contact terminal points then the entire thermostat switch needs to be replaced.

   Adjusting the thermostat:
   

4. Test the oven temperature by placing the tester in the oven's center and leaving it for 30 minutes at 350 degrees. Record the minimum and maximum temperatures of three cycles, then add those figures together, divide the result by six and you have the oven's average temperature.



5. If the average temperature is more than 25 degrees off, try calibrating the thermostat by following your appliance manual instructions for thermostat calibration.



6. Normally, thermostats are calibrated by pulling the oven's thermostat knob off, turning the knob over and adjusting the calibration ring on the back. If your oven doesn't have a calibration ring you may need to replace the thermostat.



7. To remove the thermostat:
   1. Disconnect the capillary tube and push it through the back oven wall, being careful not to break the flammable capillary tube wire.
   2. Remove the screws that secure the thermostat to the control panel and gently pull the thermostat out, leaving the wires in place.

To install a new thermostat, reverse the disassembly procedures (Step 7 above), transferring the wires individually from the old unit to the new.

There is no real way to calibrate the thermostat. Most ovens have the same problem. By lowering the setting slightly will help get a closer temperature. Sometimes similar thermostats are substituted and may not be exactly the same as the original that came with your oven. Hope my trying to answer your question was helpful, Thanks, Sea breeze

Hello, there is no fixing the thermostat although some of the older thermostats could be calibrated by using a very small flat head screwdriver in the shaft of the thermostat if there is no opening for a tiny screwdriver in the shaft then it cannot be calibrated. If you have to change the thermostat contact your local parts department have the model # handy if the original is not available ask about universal oven control replacement parts. Good Luck

Hi, those screws are for the calibration of the knob to the thermostat, so your calibration is correct. Most likely you will have to contact a servicer to check the calibration, and set you knob and plate where they will align with the actual temp again.
Hope that helps, and thank you.