Our Halstead quattro gold boiler stopped working a couple of weeks ago. We have no hot water or central heating. No lights come on to indicate lock out and the burner light doesn't come on either. We have followed the fault finding matrix in the installation instructions. The pump starts but nothing else happens. We have checked the fan, there is no 240 volts going to it. We have checked the air pressure switch by blowing/sucking through the tube and it appears okay we could hear the micro switch working. Does any one have any idea what might be wrong? Could it be one of the PCBs or a thermostat?