The TH0472 Twin channel programmer for controlling heating and hot water is designed to be as user friendly as possible. It has a large clear display, is easily programmed and suitable for gravity and fully pumped systems. Having 7day, 5/2day or 24hr and 3 on and off per day make this suitable for all applications wiether it be a replacement or on a new system. Having the industry standard back plate this makes it compatible with a large majority of existing programmers and will replace the following, Sunvic, Honeywell, ACL, Randall, Sangamo, Potterton, Horstmann, Smiths, etc, without the need to re wire.