Replacing the TRD sensor in a Thermador double oven.

Surface burners
are typically either a coil type, solid type or a ribbon coil as used in smooth top ranges. All of these consist of a heating wire that uses electric current to produce heat. Coil type elements can be checked for continuity by removing them from the terminal block and testing them with a multi-meter.You should also inspect the terminal ends for signs of heat damage or corrosion, and if present, you should replace the terminal block or receptacle at the same time. You will need to remove power from the range to change the terminal block. Solid elements and smooth top elements require raising or removing the main top to gain access. You will need to remove power from the range before lifting the main top. Continuity can then be checked with a multi-meter, once you have removed the wires from the element terminals.

On modern electronic control ranges,the oven temperature sensor
is the part thatregulates the oven temperature. If it is not working properly it could be the reason why the range or oven won't start. This part can be found inside the oven on the rear wall near the top. Most modern ovens will display a fault code if the oven sensor is at fault. If you think the sensor may be the issue you can check the resistance with a multi-meterbut will need to know the correctresistance of the sensor at room temperature. Remove power from the appliance before performing this test.

The infinite switch
on the control panel controls the power to each surface element. If you have no heat at an element and the element and terminal block check ok, then you may have a defective infinite switch. Disconnect power to the range and remove the console back panel. Locate the switch and check foroverheated wires or faulty terminals first.Test the switch's contacts for continuity with a multi-meter. If defective, replace the switch.

1. If the infinite switch does not appear to be defective, then you should check for proper voltage to the switch. This is a live high voltage test and should only be performed by qualified persons.(Locate the suspect switch for testing. Label all wires and terminals before disconnecting. A close up digital photo may be helpful.

1. On the burner control switch the terminal labeled "P" leads to the burner indicator light. The terminals labeled "H1" and "H2" lead to the burner element and the terminals labeled "L1" and "L2" (sometimes "N1" and "N2") are the power supply wires.

1. Set yourmultimeterto ohms setting x1. Turn the burner control to the highest temperature setting. Place one probe on pin "L1" and the second probe on pin "H1". The resistance measurement should be very low, zero to twenty ohms. If the test shows high or infinite resistance, the burner switch is defective.

1. Repeat the step above for the terminals "L2" and "H2".

1. If the control passes that test, turn the temperature setting to about the middle of the range and repeat the previous two steps. This will test for an intermittent problem with the switch. If the test does not show continuity with very low resistance, the switch should be replaced.

1. With the switch turned to the "Off" position, the resistance on each of the pairs of terminals tested above should now show no continuity or a reading of infinite resistance.

1. A test for continuity between "P" and "L1" when the burner control switch is on should show continuity. The light should be on whenever the control is turned on. If your test shows continuity, but the light does not operate, it is likely the bulb has failed.

If the burner switch shows high or infinite resistance, the switch is not passing along current to the burner and so the switch should be replaced. )

Most modern ovens usean electronic control board
to control the oven functions. These models will use the control board to operate the oven safety valve on a gas range or oven, and the bake and broil elements on an electric range or oven. If there is no power to the igniter circuit, or the element circuits, then you should check the control board to verify that there is power at the appropriate output relay. These are live voltage checks and should be performed by qualified persons only. If there is no output voltage then the control should be replaced.

There are two thermal switches, a high voltage capacitor, a double diode, the transformer and the magnetron itself that could be the problem . I am going to say straight up that you could get electrocuted if you dont know what to do here. To test:

HV TRANSFORMER

Remove lead wire.

Measure the resistance of the winding using an ohm meter

Primary winding 3 ohm (approx.)

Secondary winding 100 ohm (approx.)
Filament winding 0 ohm (approx)
HV CAPACITOR Remove lead wire Measure the resistance using an ohm meter set to R*1000
Terminal to terminal should momentary indicates several ohms but gradually increases to infinite.
Terminal to case should show infinite.

MAGNETRON
Remove lead wire. Install the magnetron gasket in the correct position. Check that the gasket is in good condition.
Measure the resistance of the filament terminals. Normal magnetron should be less than 1 ohm.
Measure the resistance between the filament terminal to chassis. Normal magnetron should be infinite.

HV CAPACITOR

Remove lead wire

Measure the resistance using an ohm meter set to R*1000

Terminal to terminal should momentary indicates several ohms but gradually increases to infinite.
Terminal to case should show infinite.

To cancel the F10 error, you need to unplug the oven or shut it off at the circuit breaker. Usually this error means that the oven is detecting a runaway temperature. Either the RTD (resistance temperature detector) sensor probe, the electronic oven (EOC) or the wiring is faulty.

You can check which one is bad by testing the resistance. The RTD sensor is on the back wall of the oven near the top of the cavity. It's somewhat easier to check the wire at the EOC. Unplug the connector and measure the resistance between the two wires. The resistance should be about 1100 Ohms in a room temperature environment. If you get the incorrect resistance, remove the sensor from the oven and check the resistance at the sensor. If you get the same faulty reading at the sensor and at the EOC, the sensor is probably bad. If the resistance is 1100 Ohms at the sensor, the wiring is bad. If the resistance is correct at all points, the EOC needs to be replaced.

Please add a comment with your oven's model number. I will try to find a source with the correct parts. I hope this helps.

Cindy Wells

That seems to me like it could be an issue with the sensor. Ohm it out. It should be around 1100 ohms if it is any good. Check for shorts from each wire of the oven sensor to ground. I have a manual and a TIP I wrote about these Thermadors.
Thermador 301/302 wall oven repair manual

If you need further help, reach me via phone at https://www.6ya.com/expert/dan_73bbd84fe1d95b61

The sensors should measure 1100 ohms at 75 deg F. It changes by 2 ohms per degree F.

We often see a control board failure that causes this. The control is no longer available, but you can have it rebuilt at fixyourboard.com

The F31 fault code indicates a problem with the oven temperature sensor probe. The temperature probe is secured in the top of the inside back wall of the oven. Unplug the range to disconnect electrical power. Open the oven door and remove the racks. Remove the screws that secure the oven temperature sensor probe in the back wall of the oven. Carefully pull the sensor into the oven until you get to the wire harness disconnect plug. Unplug the sensor probe. Do not let the wire harness **** back through the opening in the back of the oven. Check the resistance of the probe with a volt/ohm meter. At room temperature, you should measure about 1100 ohms of resistance. Since you are getting the F31 fault code, you will not likely measure this resistance. If the resistance is bad, replacing the oven temperature sensor probe .This should fix your problem. You can order this part from the www.appliancehelponline.com If the resistance of the temperature probe is normal (1100 ohms), then I recommend that you access the electronic oven control board in the console (with the range still unplugged ). Remove the upper back panel. Pull the P5 connector on the control board and measure the resistance through the purple wires (pins 12 and 13 as shown below) to check the resistance of the temperature probe through the circuit that connects to the board. If the resistance is drastically different than the 1100 ohms measured at the probe, then the wire harness is bad and will need to be replaced. If you measure the proper resistance through this wiring harness at the control board and the connections are good, then the electronic oven control board will need to be replaced.

Hi. The F-2 code will appear if the control board is sensing an abnormal oven operating temperature above 615F-630F, during bake, or above 915F-930F, during the self cleaning stages.

If actual over temperature condition occurred: Look for welded relay contacts on bake or broil relays. If this happens, replace oven control (also called clock or ERC).

If no over temperature condition occurred: Look for a high resistance connection or any other cause of high resistance in the oven temperature sensor circuit. Check sensor, sensor harness and sensor harness connection at sensor and oven control. Replace sensor if found defective.

Remember: Oven control (ERC) measures resistance of sensor circuit , not actual oven temperature.



NOTE_
The most common oven sensor should be approximately, 1100 ohms when at room temperature. The others may be close to as follows:
100°F - 1143 ohms
200°F - 1350 ohms
300°F - 1553 ohms
350°F - 1654 ohms
400°F - 1753 ohms
500°F - 1949 ohms