Worked for me too. Followed instructions to the letter and it worked first time.
Symptons are:
1. Programmer (is showing 'ON')
2. Digistat RFI (Roomstat) "SET" temp is higher than RFI shows as room temp)
i.e. are demanding heat
3. Boiler is "ON", not showing any error code and is not firing up.
Thanks!!
Tim "the Smallholder"
January 2010