Boilermate 2000 constantly circulating and demanding heat

I have a boilermate 2000 and the other day noticed the pump is constantly running and circulating stored water through the boiler (Baxi solo 3) all 3 pumps are set to maximum speed setting and boiler thermostat on full. The stored temp readout on the display last night was 72 degrees (which I would of thought is plenty to shut off) yet keeps running and demanding more heat. I have viewed a few threads regarding this problem and looks like I have a pcb fault. Just wanted to double check before I fork out for a new one. Is there a way to single out the fault being a thermal sensor telling the pcb the water is cooler than actual or is 72 degrees plenty to shut down? Any help would be appreciated.

Thanks.

Have answered this one for you
Mike