If one of the 2 amp fuses is blowing, it's one of three things:
Pump
Fan
Motherboard
Put a new fuse in, before running anything try the following:
Using a multimeter, look at the terminal block, terminal 9 to the boiler chassis should give you a reading of 15-25vdc, if it does, it verifies the motherboard, fuses, transformer, bridge rectifier and low voltage circuits are okay.
If the above is the case, you can try the windings on the pump and fan for resistance across the windings (L&N).
Simplier methods are to disconnect both pump and fan wiring COMPLETELY and start the boiler in a process of elimination connecting one thing at a time, the answer will soon become clear.
Carefree, April 2011