F.403 — Burner in a fault state (Ionization electrode ground fault or BCU burner control unit faulty)

What does F.403 mean?

The burner is in an error state, potentially caused by a ground fault in the ionization electrode or a problem with the Burner Control Unit (BCU).

• Ionization electrode ground fault
• BCU burner control unit faulty

Click steps to track your progress.

1. 1

   Reset the appliance.

2. 2

   If the fault persists, contact a qualified technician to check the IO electrode for a ground fault and potentially replace the BCU.

3. 3

   Ensure the appliance has been reset correctly after the initial fault.