My boiler ignites for 30 to 60 seconds, then drops out, reigniting with a bang! We have had a new PCB and Gas valve on the recomendation of BAXI. This has not cured our problem and we are at a loss to know what to do next.
Can anyone help explain what might be our problem please.

Jenny till, September 2013

check the all the spark electrodes. clean them with sand paper at the tips or replace the one that is the flame sensing one, if its not picking up the flame it will keep relighting. there not that expensive parts.

kash, September 2013