My Vokera combi boiler ignites for a few seconds then goes out and continually repeats the process. The radiators eventually warm up but theres no hot water.
I have taken the differential pressure switch out and blown through it. The relay appears to work ok. When i put it back together it worked fine for 5 mins then went back to reigniting every few seconds.

Does anyone have any other suggestions? Ive heard that maybe its the ignition pcb??

Tom, February 2008

the most common fault that you describe is the ignition pcb but check for reverse polarity first

ricky, February 2008

You heard right! the ones I've encountered are the ignition pcb (on side of gas valve)

Big A, February 2008