Your boiler's main control computer is experiencing a critical internal fault, which is preventing it from operating safely.

internal PCB failure

What causes this fault?

This fault occurs when the boiler's internal computer experiences a brief communication delay or a 'software hiccup' between its electronic components. It is usually caused by a momentary fluctuation in the electrical supply or a temporary glitch in the main control board's processing cycle. The boiler displays these numbers while it pauses to perform an automatic self-check and reboot sequence.