Low
S.34 on Vaillant Turbomax Plus 828

Your boiler has detected that the temperature is too cold and is running automatically to prevent the internal 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

From this model's manual
Verified against the Vaillant Turbomax Plus 824 828e installation & service manual, page 38.
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

Wait for the boiler to finish its warming cycle once the temperature risesEnsure your home thermostat is turned up to a normal heating levelOpen any radiator valves in cold rooms to allow circulationCheck that the condensate pipe outside hasn't frozen

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