Worcester Oval

Worcester 28i junior problem?

My boiler went off, the oval light was flashing red, I have had a quick look inside and there is a white round thing with tubes on, the round thing appears to be melted (the manual says air pressure switch), there are wires that are not melted, when I reset the boiler, the pressure goes up to max quickly and shuts down again to the flashing red light. Any ideas.

The light is a fault guide, slow or fast flash would help. The aps melting means the flame is getting out of the combustion box, the wires are heat protected. You need an engineer (corgi reg of course), have them check the expansion vessel because max pressure may mean this has gone, check the flue, fan voltage and resistance, if ok, check the heat exchanger for blockage, if that is clear, either the gas valve is not modulating, or the potentiometer (which is part of the pcb) is not working properly. I have seen this before, the pcb was not regulating the gas valve (check burner pressure in high and low mode) and fan properly in hot water mode. If you call Worcester Bosch, they may have an engineer local, if in Lancashire, they may send company I work for.

UFO over Oldbury Road Worcester 17/04/10