i am tying too repair a ferroli optimax 25 c the boiler is overheating after running for about 15 seconds the boiler bangs and then steam comes out of the auto air vent i have replaced the pump and the pcb but boiler is still playing up
double check the pump, is there power to it when the boiler lights up? if so is the shaft turning with power on, also double check the iso valves to the heating side are open.
