Y Plan System Schematic
If using a 6-wire 28mm or 1'' BSP V4043H on either circuit the white wire is not needed and must be
made electrically safe.
-11-
Mid position V
alve (not supplied)
L
N
4
1
3
1
2
4
7
6
Honeywell
ST 6400
Programmer 7 day
L
N
4
1
3
1
2
4
7
6
Honeywell
ST 6300
Programmer 24Hr
1
2
3
4
2
5
L
N
E
1
2
3
W
G
O
Bl
5
7
8
2
3
Br
Bl
Gr
Or
9
2
1
8
3
ST 6300
Room stat
Mains
V4073A1039
DHW Valve
V4043H
1
2
3
4
5
6
7
8
9
10
Automatic
by-pass
