Low
d.40 on Vaillant ecoTEC Plus 65

This code is not a fault; it is simply showing you the current temperature of the water flowing 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

Heating flow temperature: Current value

Engineer required

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

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