Replace prgrammer Elite 50 Servowarm boiler?

I have an Elite 50 Servowarm boiler in good operating order but the old programmer (Randall 700 series, Part No. B4011) has started blowing the mains supply fuse. I'm hoping to replace with a Danfos Randall FP715 Si but the conversion wiring diagram doesn't quite make sense as terminal 2 is wired on the new programmer but empty on the old. If Ian who had a similar replacement in 2007 could help me with the wiring diagram I'd be very grateful.