This code is simply an information display showing how your boiler's extra electrical port is currently configured to control external equipment, rather than indicating a fault.

Technical description

Function of relay 1 (multi-functional module): 1=Circulation pump, 2=External pump, 3=Cylinder charging pump, 4=Extractor hood, 5=External solenoid valve, 6=External fault message, 7=Solar pump (omitted), 8=eBUS remote control, 9=Legionella protection pump, 10=Solar valve