There is so little information available for these boilers, other than it's a re-badged Glow worm or Protherm, both sold via Plumb Center and Travis Perkins.
I'll make an assumption that it's not a condensing combi (given the age I seem to pick up via the net first made 2000).
Therefore, it comes down to an issue with the cross lighting pressure on the gas valve, the older gas valves light on a two stage basis (cross light to establish ignition then main flame), I'll assume therefore your cross lighting pressure is incorrect.
This is not something for you to deal with, you will need a gas safe engineer to set these up correctly.
If it is a condensing boiler and I'm wrong (it has been known) :o)) please add further and I'll look again.
Carefree, March 2011
