halstead ace high problem?

Hi, I have a problem with my hot water and heating. The Halstead Ace High boiler does not come on when a demand for heat is given for either system (CH & DHW). The green power on light is lit. On the idiot sheet the next thing that should happen is that the pump should start. It does not but the pump is ok as I have tested it seperaetly. No 240v on pins 1 & 3 of x3(output to pump from pcb). It then states the pcb is faulty. Before I buy another pcb is there anything else in the system that could hold this signal off. I have recently bled the radiators and had a couple of lockouts since over one month of doing it. One radiator did need a lot of bleeding. Is it easy to refill if need be and does anyone know the cheapest spare parts place. Many thanks.