Central heating problem

[jeburf]

***Grant Vortex Pro external combi 26e***

I drained down my central heating system yesterday so that I could drop some pipes down below the floorboards. Now the heating won't work. Have you got any ideas before I call someone in?

So far I have...
#Bled all radiators.
#Pressed service switch - pump starts for a fraction of a second then stops.
#Checked that the caps on all automatic air vents are open.
#Vented via manual air vent (water came out immediately).
#increased the pressure
#Bled the pump.

Thanks,

 

[muggles]

Why are you playing with the service switch? Have you tried turning it on via more normal methods? Have you checked that the overheat stat hasn't tripped?

 

[jeburf]

Forgot to mention that hot water is working perfectly.

The boiler is receiving demand from the timer/thermostat, I used the service switch to be certain that this isn't the problem.

The overheat has not tripped.

Joe