The hot water from my Worcester 24i RSF-L COMBI is too hot. I have no literature for this boiler and it was installed about 8 years ago. It is impossible to stand under the shower and the rads are also red hot regardless of the position of the control knob on the boiler. However if the knob is turned to anywhere near minimum then the boiler shuts down after a while. I suspect the PCB,. any body out there have any ideas