pilot light out?

I have one - the pilot lights automatically

Call for heat
Fan and Pump run
Pressure switch senses fan = OK
Pilot lights...

You may have a Fan fault - a pressure switch fault a fault with the Control board or a faulty gas valve...

http://kaijaks.co.uk/blog/nick/2008/02/10/dodgy-old-boiler

Good luck...

Peccavi
January 2010