Low Information
S.108 on Vaillant ecoTEC sustain

Your boiler is currently performing a routine self-cleaning cycle to clear any fumes from the system before it attempts to ignite.

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

Purgingthecombustionchamber,faninoperation

What causes this fault?

This status occurs when the boiler detects a need to clear the internal combustion area of any residual gases or debris before it can safely start the burner. It is a natural part of the boiler's safety protocol, triggered by the fan spinning at high speed to ensure a clean environment for ignition. This cycle is usually temporary and does not signify that a component has failed.

DIY fix possible

Wait for the process to complete, as this is a normal status message and not a breakdownEnsure there are no obstructions around the external flue pipe outside your homeIf the code persists for several minutes without the boiler firing up, try resetting the boiler once

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