I have a sabre 29he boiler its going thru the start up process with flame and fan then it cuts out the red light comes on. It then goes off and turns to green re ignites then cuts out again it does this on DHW and CH help

Think it's the PCB but there are 2

Any help would be appreciated

Clive, January 2013

check the flame electrode sensor. clean it with sand paper or replace it as this tells the boiler that a flame has been picked up if its faulty the boiler will keep trying to reignite. this is a common fault so first try this and if unsuccessful repost

kash, January 2013