What do Holiday and Hot Water Only Modes do?

Holiday Mode
Switching Holiday Mode on means that your hot water will not be heated until you switch it back off. The benefit is that you are not wasting energy heating water that you do not require, because you are away on holiday. 

Hot Water Only Mode
Hot Water Only Mode enables you to turn off your home heating but still provides you with hot water.  This mode is useful during warmer periods when you would not want any additional home heating, but still require hot water for showers etc.

Activating Both Modes
Activating both modes at the same time will turn off heating and hot water.  However, essential safety activities will still be performed.