fault code F1?

I have a Protherm 80E combination boiler it is roughly 3 years old. over the last week, daily the display shows code F1 and i have to keep reseting my boiler daily. The bar pressure varies from 1.9 to 2.2 is the pressure too high? The manual states that F1 occurs after a safety lock out. What does this mean?

Is this a major problem? can it be fixed easily? Obviously this shouldnt happen daily so any advice would be grateful.

Regards
Miss coates