F5 is the overheat fault code so depending on the type of system you have, conventional or combi i would check the pump is actually pumping, most conventional systems i.e. boiler with how water cylinder faults is the pump is running but not actually pumping.
steve
October 2011
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
