What F80 Means on a Legacy Thermador C/CM Wall Oven: Lower Door Signal Shorted Low

What F80 means

This is the lower-oven twin of F50. On older Thermador C, CM and CJ302 double ovens, F80 says the signal from the lower oven door is shorted low. The control then cannot confirm that the door is closed or latched, so the lower cavity stops. If you only see it on the bottom oven while the top works, the cause sits in the lower door circuit.

Usual causes of F80

Lower door switch or latch that has jammed or failed
Wiring at the lower door header on the power/relay board and the shared connector on both boards
Power/relay board, then control display board if the code lingers

✓ A safe check worth trying

1. Close the lower door completely. 2. Touch OFF or turn the breaker off for 3 minutes. 3. Restore power and see if F80 reappears. 4. If it does, jot down the code and your model number, and leave the lower door panel alone until we visit.

! Why you should stop here

Door circuits are tested live at the power/relay board
Replacing both boards on a guess is the costliest route
The lower door switches sit behind the door skin

Taking off a panel yourself does not by default void a manufacturer warranty, yet it can lead to accidental damage, and some manufacturers attach their own service terms. Read your warranty paperwork, or ask us, before you decide.

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More Oven codes

F24Thermador C-Series Oven F24 (F-24 in Manuals): Touch Key Stuck or Panel Blocked F63Older C/CM-Series Thermador Wall Oven F63: Wrong Lower Oven Temperature FFFF on an Older Thermador Wall Oven (SC, SCD, SM, SMW): Bad Analog/Digital Converter F25Thermador Legacy C/CM/CJ Oven Displays F25: Several Touch Keys Stuck at Once F64F64 on an Older Thermador Wall Oven (C/CM-Series): Lower Cooling Fan Air Switch Not Detected F-Thermador Wall Oven F- in the Legacy SC/SM Family: Main Board Communication Error F30Thermador C-Series Upper Oven, Sensor Shorted: F30 on C271 to CJ302 Models F70Thermador Wall Oven F70 in the Legacy C/CM Family: Lower Meat Probe Shorted

F80F80 questions

Why does only the lower oven show a code?

Each cavity has its own door and latch signals. F80 refers to the lower one, so the upper oven is usually unaffected, though we confirm on site.

Is F80 the same as F50?

They describe the same type of problem in different ovens. F50 is the upper door signal and F80 is the lower door signal. Our technician confirms this on your own unit.

What should I tell you when booking?

Give us the code, the model number on the oven frame, and whether it appeared during a clean cycle. That lets us arrive prepared. No part is ordered before you approve the written quote.