Medium
All Boilers on Viessmann A8

Your boiler is struggling to manage its settings automatically and has switched to a basic backup mode to keep your home warm until it can be adjusted.

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.

Technical description

Control mode issue

DIY fix possible

Press the Reset button on the control panelSwitch the boiler off at the fused spur, wait 30 seconds, and switch back onMonitor the display to see if the error code clears after the reboot

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