Horstmann CentaurPlus C21 and C27 two channel programmers offer up to three on/off periods a day for hot water and heating with a hot water boost and heating advance facility.
Installation and connection should only be carried out by a suitably qualified person and in accordance with the current edition of the IEE wiring regulations.
WARNING: Isolate mains supply before commencing installation.
CentaurPlus Horstmann C21 & C27 Programmer Instructions 2016-08-20
CantaurPlus Horstmann C21 & C27 Programmer Manual