My Saunier Duval 30e Won't Turn on?

My Saunier Duval 30e combi Won't Turn on, no lights etc.
The fuse is ok, I by passed the timer and it's still dead.
Prior to it not working, the water started to get luke warm, almost cold in the shower. The next day the heating didn't come on by the timer and the boiler lights were out.Could not get the boiler to come on.
Also the Boiler has a slight leak from Low Presure switch and although the low pressure light has been on for a while the boiler has worked fine.
Will replacing the Low Pressure switch fix the power problem?
Thanks