My central heating is not working - although it is still heating the hot water, the boiler is not firing up for the radiators - could it be the thermostat?
The most likely cause is a failed syncron motor in the motor valve controlling the heating. You will have one, three port valve or two, two port valves. This is usually one or two small silver boxes with a lever on the side. You can use this lever to lock open the valve to get the heating going until the motor can be replaced but you will lose thermostatic control.