F.464 — Burner in fault state: Low ionization current during calibration

What does F.464 mean?

The burner is in a fault state because the ionization current was too low during calibration, or the reading was implausible. This can affect flame detection and safety.

• Faulty ionization electrode or connecting cable (loose contacts)
• Excessive dust in the ventilation air (e.g., from construction work)
• Flue gas recirculation
• Condensate backup in the system
• Faulty BCU burner control unit

Click steps to track your progress.

1. 1

   Check the ionization electrode and its connecting cable, ensuring all plug-in connections are firm.

2. 2

   Inspect the ventilation air for excessive dust or other foreign bodies.

3. 3

   Check the flue system for recirculation and the system for condensate backup. Reset the boiler afterwards.