i have a Worcester 28cdi boiler when the hot water tap is turned on the boiler ignites fan kicks in it just gets warm at the tap then the flame goes out & the reset flashes ive changed the pcb, fan & gas valve the diverter is working correctly I must be overlooking something can anyone assist

darren, August 2014

Count the speed of the flashes and refer to makers handbook fault find

a, August 2014