Surprima 60....Lock out?

Having had my suprima 60 boiler & all its faults to go with it for 8yrs,ive now found i cannot reset it at all now...It did have 2 replacement pcb through manufacturers warranty,but i have on occasions had to rest & re light our boiler..On saturday night i noticed a noise coming from the boiler on inspection the noise was coming from the gas valve,shortly after this the boiler went out & from then wont reset. i have removed the pcb & meticulously resoldered all joints esp around the diodes where the print had started to lift,i refitted pcb & fault was still the same.Ive since put a meter over the gas valve connector & it seem to be getting power as when it tries to ignite the voltage rises at the gas valve connection. Not sure what wether to buy a pcb or gas valve,but i would have thought if pcb was faulty the voltage wouldnt be sent to gas valve? anyone got any ideas?? thanks