Low
Vitocrossal 300 on Viessmann A8

Your boiler is still providing heat but cannot accurately monitor the temperature of the water flowing into your heating system from a specific secondary pipe.

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

Regulates without supply temperature sensor (low-loss header)

Engineer required

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

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