nest Learning Thermostat Installation Manual page 13

S-plan
Power supply
for Heat Link
N L 1 2 3
230 V/50 Hz
3 A fuse
mains
L
N
N L O GR BW
Boiler Heating valve
24 24
Only required if you
have existing
thermostat wires
4 5 6 OT1 OT2 T1 T2
O GR BW
12 V power to
Water valve Hot water tank
Nest Thermostat
Y-plan
Power supply
for Heat Link
N L 1 2 3
230 V/50 Hz
3 A fuse
mains
L
N
N L BL GR
Boiler Zone valve
Only required if you
have existing
thermostat wires
4 5 6 OT1 OT2 T1 T2
O W
12 V power to
Hot water tank
Nest Thermostat
25