BoilerFaultCodesViessmann E06 Fault Code
The Viessmann E06 fault code means: your boiler is unable to start up safely because it cannot confirm that the fan is moving air through the system correctly.. It appears on 1 Viessmann model in our database.
Technical description: Burner does not start. Air pressure switch does not close.
What causes the Viessmann E06 fault?
This fault occurs when the boiler's internal safety checks fail to detect the necessary airflow required to start the combustion process. The most common reason is that the fan is either not spinning fast enough or a small rubber tube inside the unit has become blocked or perished, preventing the sensor from 'proving' it is safe to light the burner.
This fault can be more common during periods of high winds, as strong gusts can occasionally create back-pressure in the flue that prevents the air pressure switch from closing correctly.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Viessmann models that show the E06 fault code
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Source
Viessmann E06 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