Medium
C5:20 on Viessmann Vitodens 333

Your boiler has detected that the water temperature is currently below the required minimum safety level, causing it to pause heating to prevent potential condensation issues.

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

Electronic minimum flow temperature limit 20°C

Engineer required

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

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