Central heating programmers and timers

Content owner : housing@knh.org.uk Last updated : 05/03/11

Instructions for setting the on/off timers for central heating systems

Each central heating system will have a programmer or time switch that will turn the heating and hot water on and off automatically at the times you decide. You can set it to suit your lifestyle and you save money because it gives you heat only when you want it. The operation of the programmer will depend on the type of heating system and model of programmer. See the list below for instructions.


Combination boiler (No hot water cylinder)

Honeywell Programmers

Siemens RWB7 Timeswitch

Siemens RWB27 Timeswitch


System boiler (With hot water cylinder)

Honeywell Programmers

Siemens RWB9 Programmer

Siemens RWB29 Programmer