Why is my 3iE coming on during off periods?
3iE Energy-Monitoring Thermostat
On the initial set up a set back temperature should have been set, this is temperature that you would like the underfloor heating to drop down to during the off periods.
The setback temperature is the temperature the system drops down to when you do not wish the heating to be on. If the setback temperature is set too high and it falls below this the system will come on to maintain the setback temperature. If you would like the heating off completely the set back temperature should be set down to 5°C.
This can be amended by going to Menu > Set Program > Set Setback Temperature.