how can i fix my roca combi gas boiler?

I live in spain & have a victoria 20/20 combi boiler serial no.170681968 for no reason the heating pump has started to run on its own without heating being called for with a fault code 'on' at postion 90.I have a list of fault codes as supplied with the boiler but this fault code is NOT on that list.I have tried to contact roca direct but they seem as cofused as me.Can any one out there help? PLEASE ! it is now cold.

Peter H.Proud
February 2011