Broag Avanta blowing fuse on main pcb

The diverter valve cartridge insert can leak water through the spindle seal. This then can fill the diverter valve head and short out the contacts blowing the fuse on the main PCB.

Sometimes you can see a stain on the diverter body, if you remove the head and shake it you can usually hear water inside.

Order the inner cartridge assy and also a new diverter head.

This can also be the same for other boilers e.g Vokera Linea.