Low
S.0 on Vaillant ecoMAX

Your boiler is currently in standby mode because it is not receiving a signal from your thermostat or timer to provide heat.

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

No heat demand (heating operation)

From this model's manual
Verified against the Vaillant Ecomax installation & service manual, page 45.
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 that your room thermostat or smart controller is set to a temperature higher than the current room temperature.Ensure your heating programmer or timer is set to 'On' or in a timed period.Check for any low battery warnings on your wireless thermostat.

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Related fault codes

S.1View →S.2View →S.3View →

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