Override Control?

EP 2000 Electronic Programmer
In the past have attempted to override the programme but it only allows it on HW whereas would wish to on CH also. Can you please explain if the programme can be amended to facilitate this.
Must explain we have had it this way since installation but it is only now we can see the benefit as occasionally wish the heating on more frequently but this results in piping hot water that we do not use.
Thank you in anticipation of your response

Alan Cunningham
November 2010