Unox AF40 Error Code
Corrupted SD card (gas ovens only; shown with WF33).
Source: Unox/Unox_XACC-0513-EPLM_ServiceManualAll_CommercialKitchen.pdf
What does Unox AF40 mean?
AF40 is the corrupted SD card alarm on gas ovens, listed together with WF33. The control panel's SD card holding firmware and data is unreadable, and on gas models this is raised as a blocking alarm. The card usually needs re-flashing or replacing, and recovering during board changes.
Symptoms
- AF40 shown on a gas oven
- Oven stops or will not start correctly
- Firmware or settings not loading
- Alarm persists across restarts
Common causes
- Corrupted SD card data
- SD card not seated correctly
- Failed SD card
- Interrupted firmware update
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Diagnostic steps
Power cycle the oven
Restart the gas oven to see if the card is re-read.
Check the card seating
With power off, confirm the SD card in the control panel is fully inserted.
Re-flash firmware
Perform the forced software upgrade to restore the card contents.
Replace and recover the card
Replace the card if it stays corrupted; when changing boards, recover the SD card from the old control panel into the new one.
When to call a professional
AF40 is on a gas appliance and involves control-panel firmware. Re-flashing and replacing the SD card correctly should be done by a qualified Unox technician, who can also confirm the gas oven is safe to return to service afterwards.
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Other Unox Error Codes
Motor thermal protection alarm (permanent error) — the fan motor's thermal protection has tripped.
Safety thermostat alarm — the chamber safety thermostat has tripped above its limit.
Temperature probes alarm — a cooking chamber temperature probe is damaged or disconnected.
Communication error with the power board — the control board lost communication with the power board.
Gas alarm — a fault in the gas burner/ignition system (split into multiple AF23 conditions on later software).
Wrong position of Pollo valve.
Trolley is missing.
Tank missing or safety thermostat fault.
Chamber ceiling temperature too high.
Chamber over-temperature condition (Case 1: T > 150 °C / 302 °F; Case 2: T < 150 °C).
Single-point or multi-point core probe completely damaged.
Chamber temperature probe warning.