there is a very common fault on this boiler where you get a fast flash to indicate the fault and it's usually caused by the fan relay on the pcb being faulty. usual fault is, demand to boiler, pump runs, fan runs for about 2 seconds then stops, boiler goes to lockout.
if this sounds right you need a new pcb.
watch out as there ar 2 different pcb's depending on the gas valve and they are not compatible.
Ian
September 2011
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