The simplest way to connect the Boiler
Switch to the boiler is to use a single 5 core
cable; however, a 2 core cable can be used to
connect to the room thermostat terminals
and a separate 3 core to the power terminals
if necessary. This may be more appropriate if
the terminals are further apart. Ensure that
there is enough cable to reach from the boiler
to the Boiler Switch when wall mounted.
Install 1: combi boiler
Prepare the cables
The Boiler Switch also needs to take mains power from the boiler. This can be
routed from live, neutral and earth terminals located in the wiring centre. You
should refer to your boiler manual to locate them.
Locate mains power terminals
The terminals are usually located next to or
near to the ‘room thermostat’ connection. The
picture on the right shows the arrangement of
the mains (marked L & N) and room
thermostat terminals (marked 3 & 4 shown by
the loop of wire) on a typical Vaillant combi
