Low Information
T.08 on Vaillant ecoTEC Plus 836

Your boiler is currently completing a routine check of its burner system while it is in the process of starting up.

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

Burner

What causes this fault?

This message appears because the internal control board is performing a brief safety verification of the gas burner's functionality during the ignition sequence. It is a completely normal part of the boiler's startup procedure used to ensure the system is operating correctly before it begins heating. This is not a physical failure or a breakdown, but rather a standard status update from the boiler's software.

DIY fix possible

Wait for 2-5 minutes to see if the status code clears automaticallyCheck that your gas supply is active at the meterEnsure your thermostat is calling for heat

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