Medium
d.50 on Vaillant ecoTEC Plus 620

Your boiler is displaying a diagnostic setting for its internal air fan rather than a breakdown error, but it may indicate an issue with the fan's operation or the circuit board settings.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

What the manual says

Manufacturer manual

Correction of the minimum fan speed: 0 to 3000 rpm. Fan speed=Display value x 10

From this model's manual
Verified against the Vaillant Ecotec Plus 615 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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