my alpha cb28 will not reset, i've tried everything i can but only the yellow light flashes and will not fire up, it packed up a few months back and had new diaphragms fitted, any help appreciated
At once every 2 secs then that usually indicates a temperature sensor fault.
There is a primary sensor which is checked by the pcb and if out of range will not allow the boiler to fire. This is RGI work as its inside the combustion chamber. I've made this diagnosis on the info you supplied and the manufacturers instructions. I suggest that you should call an engineer and get the boiler checked.
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