Vaillant 242 boiler keeps blowing 2 amp fuses?

There is only one 'control dial'.
This could be any number of things between pump, fan, fps, and 4 pcbs, (it could even be external to the appliance).
Without delving too deep, try disconnecting the 240v motors (pump & fan), then switching on, if no fuses blow, it's a process of elimination between the two. If the fuse still blows you will need to get someone reliable in to check it as it is a potential minefield to track down.

Carefree
June 2011