Low Information
d.18 on Vaillant ecoTEC sustain

Your boiler is simply showing its current pump setting status rather than a fault; it indicates whether the pump is running constantly or only when needed.

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.

Technical description

Pump mode (Eco/Comfort)

What causes this fault?

This is not a mechanical failure but rather a status indicator regarding how your internal circulation pump is programmed to behave. It appears when the boiler is set to either run the pump continuously for constant heat circulation or only activate it during a specific heating demand. There is no physical component at fault; the boiler is simply communicating its current operating logic.

DIY fix possible

Press the 'i' or 'Back' button to exit the information menuNo further action is required as this is a status code, not an errorTo change the mode, enter the installer level settings (only recommended if you have your manual)

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Related fault codes

d.01View →d.02View →d.19View →

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