Recently moved house no instructions for central heating system but it is all working very well. Yesterday however the display on my dual channel programmer model UP2 has 'disappeared'. Doesn't show time or arrows to change Off, Timed, Once, On and I now if I try and press the select button to change the HW or CH nothing happens so they are both permanently on (red light tells me). The CH is still working perfectly and I turn the heat up and down via the thermostat in the hallway. Can anyone give me any advise? (For info we have a immersion heater for the hot water tank.)