Bar gone to red!?

Hi I wounder if any one can help ? there is no F!! problem displaying on my bolier so I dont even know if it relates to the previous issues shown, however the Bar has gone onto the red! is this serious?. It suggest s in the manual that the bar should be in the grey area but does not show or tell you how to amend if this happpens. It is a vaillant echotech plus and not even a year old. I am not using the radiators at the moment as you can imagine but surely that shouldnt be the problem. Can any one suggest a solution.