Fb High

Viessmann Fb Fault Code

Also written as FB — same fault.

The Viessmann Fb fault code means: the boiler's burner has briefly gone out while running, so it has shut itself down as a safety precaution and may need a reset or a check by a qualified engineer.. It appears on 7 Viessmann models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Flame loss in the stabilisation or operating phase
Typical repair cost £120-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Viessmann models that show the Fb fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Viessmann Fb fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026