Low
Vitocrossal 300 on Viessmann Vitopend 100

Your boiler is continuing to work but cannot accurately measure the water temperature in a specific part of your system, usually because a sensor is missing or disconnected.

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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