My Central heating does not work, but my hot water does?

Problem:  Your Central heating radiators are not getting hot, but the hot water is.

How to resolve:  somewhere near the central heating pump (near the water tank) is an Actuator which is a small electrical box sat on top of a valve. The actuator turns the valve automatically to to let water into the hot water tank, or the radiators, or both. If the actuator breaks then the valve wont turn automatically.

On the side there should be a level which is set to Auto. Try to move this to Manual whilst the central heating is switched to on, and see if the radiators get hot.  If the lever cannot be moved then the actuator head and valve need replacing.  If you can move the lever and the radiators get hot, then you can just buy a replacement actuator head (one screw, and 4 wires) and this should resolve it.