How much does it cost to fix Viessmann error code 1A, 1B?

Typical repair cost for the Viessmann 1A, 1B fault is £120-£350 including labour.

1A, 1B High

Viessmann 1A, 1B Fault Code

Q: What does the Viessmann 1A, 1B fault code mean?

Your boiler's burner has shut down because it isn't receiving enough air or fuel to ignite safely, meaning you will have no heating or hot water until it is fixed.

Also written as 1A1B — same fault.

The Viessmann 1A, 1B fault code means: your boiler's burner has shut down because it isn't receiving enough air or fuel to ignite safely, meaning you will have no heating or hot water until it is fixed.. It appears on 5 Viessmann models in our database.

Technical description: Burner blocked

Typical repair cost £120-£350 (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 1A, 1B fault code

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

Source

Viessmann 1A, 1B 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 27 April 2026