Thermador Oven Error Code F5

The F5 error code on a Thermador oven indicates that the element supervisor function for the single or upper oven has been disabled. The element supervisor is a safety and control feature within the oven's main control system that continuously monitors oven cavity temperature through the temperature sensor. When the control detects intermittent or unreliable signals from the temperature sensor, it disables the heating element supervision to prevent uncontrolled heating conditions, triggering the F5 code.

The most common root cause is a failing or intermittent single/upper oven temperature sensor, also called the RTD (resistance temperature detector) probe. This sensor provides the control board with real-time temperature data by varying its electrical resistance in response to heat. An intermittent sensor may produce erratic resistance readings or momentarily lose continuity, causing the control to lose confidence in its temperature monitoring capability and shut down element supervision.

If replacing the temperature sensor does not resolve the F5 code, the fault points to the main relay board. The relay board is responsible for switching the heating elements on and off based on commands from the control and feedback from the sensor circuit. A defective relay board may fail to properly process sensor signals or maintain stable element control, producing the same F5 condition. Diagnosis follows a sequential approach: address the sensor first, then escalate to the relay board if the error persists.