Can anybody provide schematic diagram for Vaillant combi boiler VCWA180XE?

I have some problems with heating water temperature regulation on my boiler. The heating water temperature can not be regulated with potentiometer mounted on the boiler. As I have some expirience in repairing electronics I want to try to repair that problem, but I can't find schematic diagram for Vaillant Combi boiler VCWA180XE, so please somebody send me that diagram.