Unox AL03

What does Unox AL03 mean?

AL03 is a lack-of-power alarm on the prover accessory. The prover is not receiving the electrical supply it needs to operate, so it raises this alarm. The main oven can still be used while the prover is unavailable until power is restored.

Symptoms

• AL03 shown referencing the prover
• Prover does not operate
• Main oven still usable
• Alarm persists until power is restored

Common causes

• Prover not powered or its supply tripped
• Loose or open power connection to the prover
• Circuit breaker for the prover down
• Prover power board fault

Diagnostic steps

1. 01

   Check the prover supply

   Confirm the prover is powered and its circuit breaker is not tripped.

2. 02

   Inspect the connection

   With power off, check the power connection between the oven and the prover is secure.

3. 03

   Test the supply

   Measure the prover supply voltage with a multimeter to confirm power is present.

4. 04

   Service the board

   If power is present but the prover does not run, have the prover power board checked.

When to call a professional

AL03 affects the prover accessory. A supply check may be simple, but testing the power connection and board involves mains-voltage work for a qualified Unox technician if power is present yet the prover stays off.