Your boiler's internal computer is reporting an issue with its software version, which may lead to communication problems between the controls and the boiler.

Programmer unit version: Software version of the programmer.

What causes this fault?

This fault occurs when there is a software mismatch or a data corruption issue between the boiler's internal computer and the display unit. It typically happens because the two components are unable to 'talk' to each other correctly due to a failing circuit board or a loose communication cable. Effectively, the boiler recognizes that the software version installed isn't compatible with the hardware it is trying to control.