Medium
A8 on Viessmann Vitodens 222-F

Your boiler has detected an issue with the air or exhaust flow and is currently running a self-cleaning vent cycle to clear it.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

What the manual says

Manufacturer manual

Burner blocked The venting program is started automatically (see page 62)

From this model's manual
Verified against the Viessmann Vitodens 222 F installation & service manual, page 93.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the data link between the boiler's main brain and the control screen is broken or interrupted. The most common reason is a loose internal connection or a failure of the delicate wiring that carries signals between the two components.

Engineer required

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

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Related fault codes

F8View →A9View →

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