Low
S.30 on Vaillant Home Combi

Your boiler is perfectly healthy, but it is currently waiting for a signal from your room thermostat or smart controller to turn the heating 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

Roomthermostatisblockingheatingmode.

From this model's manual
Verified against the Vaillant Home Combi installation & service manual, page 34.
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 is set to a higher temperature than the current room temperature.Ensure your smart thermostat app or wall controller is not set to an 'Off' or 'Holiday' mode.Replace the batteries in your wireless room thermostat if they are low.

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