LightwaveRF Comfy LW920 Professional Series Instruction Manual page 13

Install 1: combi boiler
Access the boiler wiring centre
The Boiler Switch needs to be wired to the room thermostat (RT) connection.
In order to locate this, you must gain access to the boiler wiring centre inside
the boiler. You should refer to your specific boiler manual to find out how to
do this. Make sure that you turn o the mains power to the boiler.
In a standard combi, the wiring centre is usually located behind the front
cover. The example shown below represents a common Vaillant combi boiler.