i trust the boiler is a 28i junior ? flashing 4 x a sec could be a sensor error or pcb , it also can be the pressure switch , seeing that you have mucked around with that part/parts of the boiler i would suspect this is the area of the prob [ could be wrong !] if u link the pressure switch wires together [ power off first !!] does the boiler work ? I STRESS IF IT DOES THE WIRES CANT BE LEFT LIKE THIS , IT IS A TEST ONLY! the pressure switch is there for a reason ! good luck
matt
November 2008