Low
Vitocrossal 300 on Viessmann Vitorond 100

Your boiler is continuing to provide heating but is unable to monitor the exact temperature of the water returning from your system, which may lead to reduced efficiency.

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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