Low
d.01 on Vaillant Home System

Your boiler is currently performing a routine cooling down process where the internal pump continues to run after the heating has switched off.

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

Pump overrun in heating mode: 1 to 60 min. Default: 5

From this model's manual
Verified against the Vaillant Home System installation & service manual.
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

No action is required as this is a normal status message and not a breakdown.Wait for the timer to finish (usually 5 minutes), and the pump will stop automatically.If the pump never stops, check that your room thermostat is not set too high.

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