Technical description
Part of the self-test sequence sequence when the appliance is switched on.
What causes this fault?
This code appears because the boiler is performing a routine electronic check of its internal sensors and components at the moment it is switched on. It is a programmed safety sequence designed to ensure everything is working correctly before the burner fires up. It is not triggered by a mechanical failure or a broken part.
DIY fix possible
Wait for approximately 30 to 60 seconds for the code to disappear naturallyEnsure the power supply to the boiler remains switched on during this processIf the code stays on the screen for several minutes, try pressing the reset button once