Medium
A5:0 on Viessmann Vitodens 050-W

Your boiler has detected that the water pump responsible for circulating heat to your radiators is not behaving as expected, which may result in your heating not working correctly.

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

Without heating circuit pump logic function

Engineer required

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

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