user manual or information?

Hi, a friend has a potterton netaheat 10-16. The fuse on the main board keeps blowing. From start, everything goes ok until the boiler starts to spark then the fuse blows. This happened with 2 fuses i put in at the same stage of ignition. Obviously there is something wrong unfortunatley they have no user manual. I suspect it is the spark generator.

Can i dis connect this generator and light manually?

Does anyone know where i can get hold of a manual online? or any advice would be much appreciated.