I have the following problem with a vokera 14 mynute se boiler. I have sparking at eletrode but no ignition. Gas valve solenoid was buzzing so I replaced gas valve with no success. I then replaced the ignition pcb but still no ignition. Looking at the manual points me towards the high limit stat but surely i would not get sparking. I have 20 mbar at gas valve inlet. The original gas valve had water in it following a recent heat exchanger split. Any help much appreciated.