Boiler on but shouldn't be

[swampydrill]

Iv'e just restarted my boiler because the wind had cut it out earlier today, currently the system is set to come on twice a day for the boiler to provide hot water but no heating, is now 10pm and after starting the boiler rather than just the pilot light coming on, the whole boiler has fired up even though it was meant to go off at 8pm which is what the timer is set to. I don't know why this is, it is a condensing boiler with hot water tank and tank in the loft etc would it be that the valves to the hot water are stuck open ?

 

[dcawkwell]

You probably have a S plan system.
A 2 port valve is stuck open. Look for the two stainless steel boxes on the pipes near the boiler or tank. Give them a sharp tap with your hand and you should hear/see the valve return to close. The boiler will then switch off.