Low Warning
db on Viessmann Vitodens 333

Your boiler has lost its connection to one of the temperature sensors used to control your heating, though it will likely keep running in a basic backup mode.

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

Control mode without room influence - Heating circuit M2 room temperature sensor shorted out

What causes this fault?

This fault occurs when the boiler loses a reliable signal from the sensor that monitors the temperature inside your living area. It is typically caused by a frayed or loose connection in the wiring, or a internal failure within the sensor itself, meaning the boiler no longer knows how warm your rooms actually are. Instead of shutting down completely, the system reverts to a basic setting to ensure you still have some heat.

Engineer required

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

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Related fault codes

daView →b7View →

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