HELP - Boiler keeps shutting down and Rads dont heat up

[paulride]

The boiler fires up but shuts down after a few minutes.
Therefore, radiators do not heat up.

I have a tank upstairs with a grundfos 15-50 pump next to it and a honeywell valve?(silver metal box with an arm on it) above that.

This morning I turned the speed dial on the pump to its highest position and the pump came to life and the rads heated up for about 20 minutes before the boiler shut down again.
When I checked the pump I couldn't hear anything and there was no buzz/vibration so I assume it stopped.
Took off the large screw nut on the front of the pump and nothing was moving inside.
So, is it that the pump has had it or is it something else that is stopping the whole lot working.

 

[gas_man_gaz]

could be the pump.. what boiler ya got? how many valves ya got? (silver metal box's) did ya check there was power to the pump? is the fault jus on the central heating or does it affect the hot water?

 

[paulride]

could be the pump.. what boiler ya got? how many valves ya got? (silver metal box's) did ya check there was power to the pump? is the fault jus on the central heating or does it affect the hot water?

The bolier is an old concorde and there is only one honeywell valve.

The pump started this morning for about 20 minutes on highest speed so it certainly had power to it at that point, although I did smell something different so maybe it was burning out but then again maybe I was just imagining it.

How would I know if there is power to it?
the valve seems to have power to it.

 

[gas_man_gaz]

have ya got a multimeter? ya didnt say if ya hot water was affected?

 

[paulride]

have ya got a multimeter? ya didnt say if ya hot water was affected?

Whats a multimeter?

I can get some hot water but the boiler keeps shutting down after about 2 or 3 minutes so it is never going to get really hot