2F:2 Low

Viessmann 2F:2 Fault Code

Also written as 2F2 — same fault.

The Viessmann 2F:2 fault code means: your boiler is currently running a maintenance program intended to purge air from the system after it was recently filled with water.. It appears on 6 Viessmann models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Filling program active

DIY fix possible

Wait for the filling program to complete automatically, which usually takes about 20 minutes.Ensure your heating controls are set to a demand state if the boiler does not exit the mode on its own.If the code persists after 30 minutes, switch the boiler off at the fused spur for one minute and turn it back on to reset.

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Viessmann models that show the 2F:2 fault code

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

Source

Viessmann 2F:2 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