Most boilers are fitted with a timer that's usually represented by a 24-hour dial or a digital readout. The timer will display when the heating and hot water are set to switch on and off, with at least two opportunities to do so during a 24-hour period. In the morning, set both to switch on 20 minutes before you get up and switch off 15 minutes before you leave the house. In the evening, set them to switch on 15 minutes before you get home and switch off at least an hour before you plan to go to bed.
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