I have a Gloworm spacesaver kfb50, Grundfos 15/50 pump, Sunvic SD 2701 three port actuator. The hot water works fine but the heating won't work at all. I've put the thermostat right up and switched the heating on either with the hot water or on it's own but cannot get any heating. The pump is working and comes on when the boiler fires up but the diverter valve does not seem to allow any hot water into the central heating. If I move the lever on the side of the diverter I can feel the pipe on the central heating side get hot but it automatically moves back once I let go. So my questions are, 1 :Is it probably a broken valve motor or could the programmer/thermostat just not be "telling" it to open? 2: Is it acceptable to take the valve motor off and manually open the valve so allowing some heating for a period of time? The valve does move quite easily if I lift the motor off. P.S The system has been intermittantly creating a droning noise of late ( sounds like a Lancaster bomber circling the house) and the central heating has been going on and off without reason. Thanks for any suggestions.