Dacor Range, Oven, Cooktop Error Code U21

The U21 code on a Dacor oven indicates that the upper or single oven cavity exceeded 890 degrees Fahrenheit during the self-clean cycle. This is a safety fault that automatically stops the cleaning process to prevent thermal damage to the appliance. The oven needs to cool down fully before any further diagnostics or operation. Common causes include a faulty temperature sensor, a poor door seal, or a malfunctioning control board.

Resetting the oven by cutting power at the circuit breaker for several minutes may temporarily clear the U21 code, but it will not fix the underlying problem that caused the over-temperature fault. If the faulty component, such as a worn door gasket, drifting temperature sensor, or tripped thermal limiter, is not addressed, the U21 code will return the next time the self-clean cycle is attempted. A reset should only be used as a first step in diagnostics, not as a permanent fix.

Repair costs for a U21 fault vary depending on the failed component. A replacement oven temperature sensor typically costs between 30 and 80 dollars for the part, while a door gasket or latch assembly can range from 20 to 100 dollars. Control board replacement is the most expensive scenario, often ranging from 200 to 500 dollars or more for parts alone. Adding professional labor, total repair costs can range from 100 dollars for a simple sensor swap to 600 dollars or higher for a control board replacement.

You should not attempt to run the self-clean cycle again until the underlying cause of the U21 fault has been identified and corrected. Normal baking and cooking may be possible after the oven has fully cooled and the error has been cleared, but running the self-clean mode again without repair risks repeating the over-temperature event. If the temperature sensor or thermal limiter has failed, the oven may also behave erratically during normal cooking, so a technician inspection is strongly recommended before continued use.

Start by allowing the oven to cool completely, then check the oven temperature sensor by measuring its resistance with a multimeter, looking for approximately 1080 ohms at room temperature. Inspect the door gasket for damage and confirm the door latch engages fully during the self-clean cycle. If those components appear normal, a technician should evaluate the thermal limiter, heating elements, and control board. Parts like the RTD sensor and door gasket are generally straightforward replacements, while control board replacement requires more advanced diagnosis.