I fitted this about 5 yrs ago and it now has an intermitent fault and it goes to lockout , the fan runs then it doesnt try to ignite and it goes to lockout , I have checked the fan is ok the tubes are ok and the air pressure switch semms ok , I have now proved that the air pressure switch is ok by looping out the wires to the switch and the same thing happens , I then thumped the boiler on the circuit board housing and it is now running , last time I did this it ran for four days then the same thing happened , so i now think it has a faulty pcb , anyone else think of anything else it could be ??????Cheers