LightwaveRF Comfy LW920 Professional Series Instruction Manual page 18

Install 2: Y plan
2. Wiring to a Y plan heating system
The basic diagram below shows the main constituent elements of a Y plan
system which is common in larger houses. The system boiler produces hot
water which is stored in the tank and/or circulated in the central heating
system. A motorised valve allows flow to the tank, the radiators or both
together. A room thermostat controls the flow to the heating by opening or
closing the valve. This thermostat needs to be disconnected at the wiring
centre and replaced by the Boiler Switch.
Wiring
centre
System
boiler
Motorised
valve
Heating & hot water