Worcester greenstar 18ri fan blown?

There is normally a 3 amp glass fuse on the PCB
I believe Worcester normally leave a spare one inside the PCB cover
Try replacing the glass fuse on the PCB BUT leave the fan molex disconnected
Phone Worcester technical helpline to help guide you through the rest of the test procedure
You will require a multimeter at hand

Q
September 2015

Well there's a choice

Leave the fan as it is = no heating or hot water
Change the fan = Medium expense
Have the fan changed for you = more expensive
New boiler = very expensive

You can always remove the fan and bench test it before you decide.

Good Luck...
September 2015