Jo asked ... How to engage clutch on old sewing machine to engage needle?    |    Jacky asked ... Miele Vacuum cleaner?    |    Ben asked ... Toyota Yaris French or Japanese?    |    Andy asked ... How can I mend my MacAlistair 450w hedge trimmer?    |    Felix asked ... Hitachi vt-m70em?    |    Click here to ask your question

F5 fault showing on boiler?

I have a Vitodens 1000 it is 12 months old and is showing a F5 fault on the panel, please could you tell me what this is.
Pammie, October 2010
link Click here to see other fixes for Viessmann 1000.