How Oven Temperature Sensors Works

Photo of an oven temperature sensor with a plastic molded connector

And oven temperature sensor is actually a thermistor. A thermistor is a device that when its temperature changes its resistance to the flow of electricity changes. This works with all temperature sensors whether it is on a gas or electric range. Detachable probes that you insert into an item you are cooking to check it’s temperature work the same way.

Range and oven manufacturers found that they could not only maintain the temperature of the oven cavity more evenly using a temperature sensor, but they could also save money. It is a lot less expensive today to have an electronic control board and a sensor in a range or wall oven than to use an old-style thermostat.

So how does an oven temperature sensor actually work?

As a temperature in the oven cavity increases the resistance to the flow of electricity in the oven sensor begins to change. In other words as it heats up it starts to resist the flow of electricity / electrons through it. The oven electronic control board constantly sends out a small electrical current and measures the amount of electricity that returns to the control board. The logic or the computer inside the oven control has been designed to interpret this electrical resistance as temperature. Then it displays it so that humans can read it on the electronic control display.

If an oven sensor fails or starts to give erratic signals to the electronic control board, the control board has also been designed to give an error code in the display. These codes vary among manufacturers but for example you may see an F1 or an F3.

Oven temperature sensors that are erratic or intermittent are difficult to diagnose because they need to be connected in the circuit to find out if their resistance is changing properly while they are being heated in the oven cavity. The best you can do is to find out what the resistance for your particular sensor is supposed to be at room temperature. Then you can use an ohmmeter to check it’s standing resistance. Often times you will find it will be in the normal range at room temperature.