VERIFIED
One oven healthy, one not
Double wall ovens put two cavities and often two sets of controls in a single column. When E28 appears on the upper oven while the lower one bakes without complaint, that contrast is a gift: it rules out the shared supply and points inward.
E28 has no confirmed definition in the material we use, so we lean on that kind of detail. The code alone cannot name the failed part, so the cavity it appears on and what the other cavity is doing at that moment become the evidence.
How to read the contrast
- Code on only one cavity suggests that cavity’s sensor, element or relay.
- Code on both cavities suggests something they share, such as supply, board or cabinet heat.
- Code when both cavities run together points toward load or temperature around the controls.
A Sunday dinner example
The lower oven roasts, the upper oven warms rolls. Midway, E28 appears on the upper one, which goes cold. The owner swaps the rolls into the lower oven and carries on, then notes that the upper oven worked fine the day before when used alone.
What is checked first
The suspect cavity’s temperature sensor and its element, then the relay and the board channel that serve that cavity. The sensor reports cavity heat to the control, and the relay switches power to the element, so a fault in either can leave one cavity cold. The wiring between the cavities, and the cooling airflow of the column, are checked next, since the upper oven sits in the warmer air.
Checks that stay outside
- Run each oven alone for a plain bake and see which one shows the code.
- Record how long each had been on when E28 appeared.
- Check that nothing blocks the vents at the top and bottom of the column.
Resist the urge to swap racks or trays between cavities to test, because that adds variables without helping.
What to tell us
Name the cavity, the mode and the order in which the ovens were switched on. A technician will then test that cavity on its own and then both together. The diagnosis precedes the written estimate, and no part is replaced without your go-ahead.
Why the upper oven runs warmer
Heat rises, so the upper cavity of a column breathes warmer air than the lower. That is one reason an upper-oven code gets extra attention when it appears only after hours of use. Tell the technician how long the lower oven had been on beneath it.
Frequently asked questions
Not necessarily; testing each alone shows whether the problem is specific to one cavity.
It separates a problem in one cavity from one in the shared parts.
If it heats normally and shows no code, yes, with care.
Usually one; the technician tests both in the same appointment.
Model compatibility: Bertazzoni reuses codes across series and model years, so E28 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
