Horstmann Series 527 is a 7-day central heating programmer that gives you full control over your heating system. You can set up to three on periods per day, and the programmer will automatically switch your heating on and off at the times you specify. The programmer also has a boost function, which allows you to get hot water on demand, and an advance function, which allows you to start a heating period early without altering the time or programme settings. The Series 527 is easy to use, with a clear display and simple controls.