Grundfos Alpha+ 25-60 pump problem?

the Grundfos pump circulates water in my UF heating system however, I have noticed lately that although my living room feels at least aired, the kitchen area which is tiled, is still very cold - this wasn't previously the case as the tiles were always pretty warm and the room was a good deal warmer. My boiler fires OK and the pump feels warm and there is certainly hot water flowing into the exit manifold pipes. There is no sound from the pump whatsoever, neither can I feel it running - is this normal with this pump? Is it possible that the pump has packed in and this is the cause of the reduced heating? The pump is around 5 years old and the heating system is controlled by a Horstman Centaur (default factory setting)