My vokera rs20 - 80 boiler pilot light works and stays on but the boiler does not fire up, the fan works, hence no heating or hot water. I have had a new gas valve, igniter and variour other small items replaced (diapraghms). This has now been ongoing for three weeks and my corgi engineer has ran out of ideas. he has done electrical tests on the pcb and he says this is ok, he now thinks that the air pressure switch is the problem. Can anyone suggest a cure for this problem as the cost is now huge.
Daffyboy