Ariston microgenus HE 24 combi-boiler PCB 2A fuses keeps blowing out?

The boiler is about 2 years old and it has started blowing fuses. All was well until last week. The boiler didn't start. When I looked at it the power light was off. I checked out the system and found the two 2 amp fuses on the PCB blown. The fused spur was still ok. I have since replaced the fuses and the boiler fires up for a while and then there is a flash as the fuses blow again. I replaced the fuses again and the same happend, I then replaced the fuse with delay action. The boiler worked fine for a week and found it blown again.