Low
D.19 on Vaillant Atmomax

Your boiler is currently switching between different pump speeds to manage the flow of water through your heating system.

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

Operating modes of the two speed heating pump

DIY fix possible

Check if all radiator valves are fully openMonitor the boiler to see if the status code clears during normal operationEnsure the system pressure is between 1.0 and 1.5 bar

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