I have a simple problem. Potterton Suprima 80 boiler. Problem since new 1 year old. The boiler does not stay on long enough, I have temp guage on the outlet copper pipe from boiler newer goes much above
60degree. I have had the circuit board changed, the temp sensor changed, as recommended by various plumbers. Yet I have the same problem. The temp control knob is on max. The same problem, the boiler stays on for 2mins then goes off. Why does the dam thing not stay on!!!Anyone who has a solution, or have had similar problem most welcome to contribute.