Direct answer: When a Flex Duo lower oven will not heat, the usual culprits are the cooking mode or divider setup, a lower bake element that is not coming on, or a lower oven temperature sensor reading wrong. Start with the setup checks before you assume the electronics are bad.
Most likely: The most likely fix is correcting the oven mode or finding that the lower oven bake element is not heating even though the oven appears to start normally.
First separate a setup problem from a real heating failure. If the display accepts a bake cycle but the lower cavity stays cool, watch and listen during the first few minutes. A working lower oven usually gives you heat from the bottom pretty quickly. Reality check: a lot of "not heating" calls turn out to be a mode or divider issue on dual-cavity ovens. Common wrong move: replacing parts because the fan runs or the panel lights up, even though the lower bake element never got checked.
Don’t start with: Do not start by ordering an oven control board. Control failures happen, but they are not the first thing to bet on when one cavity is the problem.
The display starts a bake cycle, but the lower cavity stays room temperature and you do not feel bottom heat after several minutes.
Start here: Start with mode, divider, and door checks, then confirm whether the lower bake element is heating at all.
The cavity gets a little warm, but preheat takes too long or never finishes.
Start here: Look for a lower bake element that is partially failed or a lower oven temperature sensor that is reading wrong.
One mode seems to work, but regular bake in the lower cavity does not cook normally.
Start here: That points more toward a lower bake element problem than a full power loss.
The appliance has power and at least one cavity still operates, but the lower section will not heat correctly.
Start here: Treat this as a lower-cavity component or setup issue first, not a whole-oven power problem.
Dual-cavity ovens can act dead in one section if the divider is not seated right or the selected cooking mode does not match the cavity setup.
Quick check: Remove and reseat the divider if your setup uses it, then select a plain lower-oven bake cycle and start it again.
If the lower cavity stays cold or only gets mildly warm, the lower bake element may not be glowing or producing enough heat even though the oven appears to run.
Quick check: Start bake and carefully look for heat from the bottom area after a few minutes. A visibly damaged, blistered, or split element is a strong clue.
A bad sensor can make the control think the lower oven is hotter than it really is, which causes weak heating, long preheat times, or early shutoff.
Quick check: If the lower oven starts warming but stalls far below the set temperature, the sensor moves up the list.
If setup is correct and the lower bake element and sensor check out, the control may not be sending power to the lower heating circuit.
Quick check: This becomes more likely when the display works normally but the lower bake element never energizes and no obvious element damage is found.
These ovens can look like they accepted a cycle when the cavity setup is the real problem. This is the fastest no-parts check.
Next move: If the lower oven now starts heating normally, the issue was likely setup-related and no repair part is needed. If the cycle starts but the lower cavity is still cold or barely warm, move to the lower heating checks.
What to conclude: A lower oven that comes back after reseating the divider or restarting the cycle usually had a configuration issue, not a failed part.
The lower bake element is the most common single part behind a lower cavity that will not heat right on an electric oven.
Next move: If you confirm strong bottom heat and normal preheat, the bake element is probably not your problem. If the lower cavity stays cold or only gets weak heat and the element shows damage, the lower bake element is the leading suspect.
What to conclude: A damaged or non-heating lower bake element can leave the oven completely cold or make it heat so weakly that preheat never finishes.
If the lower oven warms some but never reaches the set temperature, the sensor can be lying to the control and shutting heat down too early.
Next move: If the lower oven reaches and holds temperature normally, the sensor is less likely to be the issue. If heating starts but cuts short or temperature is way off without visible element damage, the lower oven temperature sensor becomes the best-supported part to replace.
A bad seal will not usually make the lower oven stone cold, but it can make preheat drag and cooking results look like a heating failure.
Next move: If the door now closes tighter and the lower oven holds heat better, you may have solved a heat-loss problem. If the lower oven is still not heating or is far off temperature, go to the final decision step.
By now you should know whether this is a setup issue, a lower bake element failure, a sensor problem, or something deeper in the control circuit.
A good result: If the lower oven now preheats normally and holds temperature, run a full bake cycle to confirm the repair.
If not: If the lower cavity still will not heat after the supported part repair, stop buying parts and have the control circuit diagnosed professionally.
What to conclude: The strongest homeowner repair paths here are the lower bake element, then the lower oven temperature sensor, with the door gasket as a heat-retention fix when damage is obvious.
Repair Riot may earn a commission from qualifying purchases, at no extra cost to you.
That usually points to a lower-cavity issue, not a whole-oven power problem. Start with the divider and mode setup, then check the lower bake element and lower oven temperature sensor.
Yes. A lower bake element does not always fail completely open right away. It can heat weakly or unevenly, which gives you very slow preheat and undercooked food.
No. On a one-cavity heating complaint, controls are usually farther down the list than setup issues, a failed lower bake element, or a bad sensor. Save the control diagnosis for after those checks.
Usually no. A bad lower oven door gasket more often causes slow preheat, heat loss, and uneven baking. If the cavity stays completely cold, look harder at the lower bake element or control path first.
The usual clue is an oven that starts warming but never reaches the set temperature, or claims preheat is done when it is obviously still too cool. If you can test the sensor with power disconnected and it reads clearly out of range, that confirms it.
No. Stop using it and inspect for a damaged lower bake element, burned food on the element, or overheated wiring. A strong electrical burn smell is a good reason to stop and call for service.