i have a vokera aquanova water heater which has a flashing green light ,it goes through the ignition sequence several times before going to a permanent red light. can hear fast clicking noises from the pcb area also cannot see any sparks from electrode . Burner etc looks very clean , fan is also working ,that leaves the gas valve ,pcb and differential pressure switch to be checked. Anyone got any idea as to what could be wrong with it?.Thanks

j.smith, July 2010

Youre right about the pcb,after checking the pcb it turned out to be a loose connection/bad contact on one of the wires in the connector block ,who would have thought it would be something as small as that! good job i didnt fork out £150 for a new pcb!.Thanks for the good advice.

j.smith, August 2010

1/ Check the gas is available:
2/ Check ignition is occuring at the burner:
If sparking is at the burner and the gas is available, there are only two options left.
Power at the gas valve when sparking occurs?
Yes: Gas valve is at fault
No: Pcb is at fault

Carefree, July 2010