Low
S.34 on Vaillant ecoTEC Plus 826

Your boiler has detected very cold temperatures and is automatically warming its internal components to prevent the pipes from freezing.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Frost protection mode active

From this model's manual
Verified against the Vaillant Ecotec Plus 826 installation & service manual, page 48.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Ensure your heating is set to a low temperature or the frost protection setting during cold snapsKeep your boiler switched on at the wall and the gas supply turned onCheck that the external condensate pipe is not frozen or blocked if the weather is extremely cold

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Related fault codes

S.30View →S.31View →

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