Hot Water, Cold Radiators, Grant Vortex 15-26

[rstark]

Hi

The boiler fires up when I run the hot water no problems.

The central heating is on, turning the wall thermostat is sending a message as the makes the central heating valve whirl open (pictured below), this valve also has very hot water both sides, i can hear the pump running in the boiler, but the burner itself does NOT fire. It is not in lockout mode or overheat, any suggestions please?

 

[rstark]

Just an update radiators are getting luke warm only but not really heating up (I also bled them to see if it helps) the burner is coming on occasionally, maybe when hot water is required? but it doesnt stay on long..left message with Plumber