The federal government enforces strict guidelines onto energy efficient products such as the iStore, as such the thermostat band is 12 degrees. If you check your lcd screen it has two numbers, the small number in the top left is the bottom of the tank temperature and this controls the heating cycle. When the bottom drops to 12 degrees below the target temperature then the heating cycle will commence. Typically your iStore would be set to 60 degrees, this can be checked by pressing the up arrow once to display that target. Following a 60 degrees target the bottom of the tank needs to drop to 48 degree to start the heating. Note that the hot water always rises and will stay at the top of the tank during usage and delivery to the house so if you see say 55 in the centre and 35 in the top left the house will still be getting 55 degree water from the tank.
