Rafal Kaczynski
Dear Aine it seems to be like explosive ignition in your boiler. I would suggest to turn boiler off and call for gas engineer . Explosive ignition can be caused by cracked burner or ignite probe or also common fault on Worchester boilers pcb is delaying a spark. ( gas valve is open while is no spark to ignite ) I hope this can help. Regards Rafal
