Low
d.18 on Vaillant Home System

Your boiler is simply showing its current pump setting and is not experiencing a fault; it is just letting you know whether the pump is running constantly or intermittently.

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 overrun operating mode: 1=Comfort (continuously operating pump), 3=Eco (intermittent pump mode)

DIY fix possible

Observe the display to see if the status code clears when the heating cycle finishesCheck the user manual if you wish to change between 'Eco' and 'Comfort' modesNo action is required if your heating and hot water are working as expected

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Related fault codes

d.01View →d.19View →

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