Potterton heatmax combo 24HE

[middlehouse]

I had a potterton heatmax combo fitted about 5 years ago now. for some reason this year we have been having a problem with the heating.
The hot water works fine all the time when the nob is on hot water. but when we switch the nob to do the radiator and the hot water the boiler cuts out with the code E168.

Does anyone know what the problem could be.

 

[Agile]

It could be a faulty PCB.

But it could also be something else. As with all boiler faults it needs proper diagnosing.

Its a combi boiler.

Tony