Hi . if the pump runs and the fan runs it can only be the air pressure switch . check you didn't disconnect anything from the board accidently
have replaced the air pressure switch.top of boiler behind the fan
Ok . can you hear it spark ( attempt to light ) ?
tried to test spark with a spare electrode ,removed starter electrode end plugged in the circut board put in spare and held spark end 4 mm near to burner side case .no clicking or spark
Ok . check overheat stat isnt faulty . there is a sensor on the condense trap which could be an issue. I think this if faulty stops ignition. But I think most likely to be the ignition PCB .if you have a multi Meter you can check the stat for continuity ..
The condense trap sensor could be at fault though . see what reading you get through it
.changed circuit board for a new one. no luck.will come back family duty calls