What is the difference between comfort mode and ECO mode for DHW heating?

In comfort mode, the appliance is continually maintained at the set temperature, providing shorter delay when the hot tap is running but using more gas. In ECO mode, heating to the set temperature only begins when the hot water tap is opened. To set ECO mode, press the eco button until 'eco' appears on the display; press again to return to comfort mode when 'eco' disappears.