central heating won't fire up

[ColinMcK]

when switching the central heating on the boiler doesn't fire but when the hot water is switched on boiler fires and heats water.

The light does come on the control panel when the central heating is switched, just doesn't fire.

Any ideas?

 

[seco services]

need more info on the system ie motorised valves etc.

 

[bengasman]

Probably something wrong somewhere.
For more accurate diagnosis we need more accurate info; most of us have sold the crystal balls due to the recession.