What C-21 Means
C-21 means the internal temperature rose abnormally high. On a Dacor wall oven the control compares the cavity reading against what the selected mode should produce, and C-21 is its response to a temperature it did not command. It is a protective shutdown.
Common Causes of C-21
- Heating element relay welded closed so an element stays on
- Temperature sensor reading low, so the control over-drives the elements
- Cooling airflow blocked so heat builds up around the cavity
🔧 One Safe Check You Can Try
Switch the oven off and let it cool completely with the door closed. Then do Dacor’s restart and breaker reset. If the code happened during an ordinary bake, not a self-clean, and returns, do not use the oven until it has been checked.
⚠ Why You Shouldn't Go Further Than That
- A relay stuck on keeps heating regardless of the control; testing it means working on the live control board.
- Overheating can scorch cabinetry around a built-in oven, so the cause has to be found before the next use.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.