Medium
dE on Viessmann Vitodens 300-W

Your boiler has lost connection with the sensor that monitors the temperature for your second heating zone, meaning it cannot accurately heat that specific area of your home.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Heating circuit M2 room temperature sensor lead break

Engineer required

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

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