Hi, I have a Drayton MA1 mid-position actuator which I think has failed but would appreciate views. My hot water seems to run OK but I have no central heating. I have removed the clip-on actuator and can turn the valve to either side OK by hand. I cannot move the black button on the actuator and when I removed it a small spring fell out, also there's something loose inside it as it rattles when shaken. Is it likely that the actuator has seized and if so would I be wasting my time replacing the synchronous motor, also is it logical that the central heating pump doesn't come on if the actuator isn't turning?