BoilerFaultCodesViessmann 50:0 Fault Code
Also written as 500 — same fault.
The Viessmann 50:0 fault code means: your boiler's computer screen and main control board are having trouble communicating with each other.. It appears on 2 Viessmann models in our database.
Technical description: Alternative control (automatic adjustment upon recognition of the operating interface)
What causes the Viessmann 50:0 fault?
This fault occurs when the boiler's internal computer brain loses its connection with the display screen on the front of the unit. The most common reason is a loose or damaged data cable connecting the two parts, or an electronic failure within the display module itself. Because the components can no longer 'talk' to each other, the boiler stops working as a safety precaution.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Viessmann models that show the 50:0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 50:0 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026