Your boiler is currently in a manual testing mode used by engineers to check its performance rather than a standard fault, meaning it is not operating normally for your home heating.

DIY fix possible

Locate the reset or 'service' button on your boiler control panelPress and hold the service button for several seconds until the display reverts from the number to a standard standby symbolOnce the display shows a normal status, turn on a hot water tap to ensure the boiler returns to standard operation