Low
d.1 on Vaillant ecoMAX 622

Your boiler is currently running its internal pump to move leftover warm water away from the heat exchanger to prevent overheating, which is a normal part of its cooling cycle.

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

Heating system pump over run

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

d.0View →d.2View →

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