Medium
222-F on Viessmann A8

Your boiler has detected trapped air inside the system and is currently trying to clear it out to prevent the burner from overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Burner blocked. The venting program automatically starting

DIY fix possible

Wait for the automatic venting program to finish (this usually takes 20 minutes)Check that your radiators have been bled and no air is trapped in themEnsure the boiler's water pressure is between 1.0 and 1.5 bar

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