looks like you wasted your money, it looks like the pressure switch isnt making contact, which in turn doesnt send signal to fan to stay on. This would be first thing to check ,then if that is ok it has to be the fan itself,look for scorching etc on coil on fan.
one more thing ,its actually illegal to work on boilers if your not Gas Safe, so wot ye doing anyway!! im only telling you how to fix it because i feel pity 4 u
Paul Spiller-Chilli Heating, August 2009
