Low
S.30 on Vaillant ecoTEC Pro 30

Your boiler is currently waiting for a signal from your room thermostat or smart controller, which is preventing the heating from turning on.

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

Room thermostat (RT) is blocking heating mode

From this model's manual
Verified against the Vaillant Ecotec Pro 30 installation & service manual, page 35.
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

Check your room thermostat or smart hub to ensure it is set higher than the current room temperature.Replace the batteries in your wireless room thermostat if applicable.Ensure your thermostat is not in 'holiday' or 'summer' mode.

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Related fault codes

S.31View →S.32View →

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