Low
d.73 on Vaillant Ecomax Condensing 600/800 series

Your boiler is struggling to accurately read or maintain the temperature for its quick-start hot water function or solar heating setup.

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

Offset warmstart temperature value / For solar applications: Switching difference for the solar pump

Engineer required

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

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