Hi, Had new boiler and this thermostat installed last year. Worked perfectly but today the screen on the thermostat was blank, so I replaced the batteries and it came back on but its saying the room temp is 40 degrees (its cold and raining). I've tried taking batteries out again but comes back on saying the same. I couldnt find a way to reset it apart from taking batteries out. Any ideas? At the moment I can't put the heating on as the max temp the heating will go up to is 35 degrees!!!