can i get a circuit diagram for this PCB? If i can i could fix the PCB?

You do not say the boiler details - just PCB
You may not need a circuit diagram
They commonly suffer broken down electrolytic capacitors and dry joints

A digital photo will give you confidence when you come to put it back together

Here's a link to a pcb repair on a Potterton Profile...

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

Good luck...

Peccavi
January 2010