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AF40Unox

Unox AF40

Corrupted SD card (gas ovens only; shown with WF33).

Source: Unox/Unox_XACC-0513-EPLM_ServiceManualAll_CommercialKitchen.pdf

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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

Diagnostic steps

  1. 01

    Power cycle the oven

    Restart the gas oven to see if the card is re-read.

  2. 02

    Check the card seating

    With power off, confirm the SD card in the control panel is fully inserted.

  3. 03

    Re-flash firmware

    Perform the forced software upgrade to restore the card contents.

  4. 04

    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.

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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

AF01

Motor thermal protection alarm (permanent error) — the fan motor's thermal protection has tripped.

AF02

Safety thermostat alarm — the chamber safety thermostat has tripped above its limit.

AF03

Temperature probes alarm — a cooking chamber temperature probe is damaged or disconnected.

AF04

Communication error with the power board — the control board lost communication with the power board.

AF23

Gas alarm — a fault in the gas burner/ignition system (split into multiple AF23 conditions on later software).

AF24

Wrong position of Pollo valve.

AF25

Trolley is missing.

AF26

Tank missing or safety thermostat fault.

AF39

Chamber ceiling temperature too high.

AF41

Chamber over-temperature condition (Case 1: T > 150 °C / 302 °F; Case 2: T < 150 °C).

AF43

Single-point or multi-point core probe completely damaged.

WF01

Chamber temperature probe warning.

View all Unox error codes →