I'm wondering this due to the wiring indication that came with the valve, and also the number of wires in the connecting box.

The programmer is fitted with a non-rechargeable, non-serviceable long life battery, which will maintain the programmed time settings with the mains supply disconnected.Lower the front flap of the unit. On third Channel press the ADVANCE(Enter) and SELECT(Blue) buttons together then release the buttons and the programmer will return to the preset factory settings. The old thermostat can't simply be disconnected as this would leave the heating wiring 'open circuit' and the heating would not operate; the integrity of the circuit needs to be maintained. ChannelPlus series 2 programmers are suitable for mounting on a flat surface only, they must not be positioned on a surface mounted wall box or on unearthed metal surfaces. ELECTRICAL CONNECTIONS

Designed for use with fully pumped central heating systems, using three separate two-port zone valves. For reasons of space and clarity the diagrams has been simplified, for instance some Earth connections have been omitted. Other control components shown in the diagrams i.e. Valves, RoomStats etc. are general representations only. However the wiring detail can be applied to the corresponding models of most manufacturers e.g. Horstmann, Honeywell, Danfoss Randall etc.

Frequently Asked Questions about Horstmann ChannelPlus H37XL Thermostat

Ideal for the control of two heating zones as well as hot water via separate thermostats and zone valves (e.g. zones 1, 2 and 3 or hot water, heating 1 and 2).