
23
intelligently applied technology
© Baxi Heating UK Limited 2005
Fig. 20
Typical System Wiring
NC
C
Room
stat
Cyl
stat
NO
C
N
NC
N
HW on
E
HW off
L
CH on
Pump
Mains
This
Appliance
m
ust
b
e
E
ar
thed
N
N
L
EE
SwL
L
Optional
e
xter
nal
prog
rammer
Fused 3A
Mains Supply
F
rost stat
T
ypical wir
ing centre
12 w
a
y sho
wn
Mid position v
alv
e
br
b
g/y
br
b
g/y
Pump
supplied
from
boiler
789
41
0
5
E
N
L
17
28
39
41
0
56
6
11
11
12
12
T
ypical System
Wiring - mid position v
alve (Y Plan)
Exter
nal Prog
rammer
Mains supply direct to wir
ing centre
The Pump can be wired through the wir
ing centre
b
ut m
ust be wired direct to Pump L, N & Ear
th
on boiler ter
minal b
loc
k.
b - b
lue
br - bro
wn
g/y - g
reen y
ello
w
Boiler PCB
NC
C
N
HW on
E
HW off
L
CH on
Pump
Mains
This
Appliance
m
ust
b
e
E
ar
thed
N
N
L
EE
SwL
L
789
41
0
5
E
N
L
17
28
39
41
0
56
6
11
11
12
12
Optional
e
xter
nal
prog
rammer
Fused 3A
Mains Supply
F
rost stat
Not used
T
ypical wir
ing centre
12 w
a
y sho
wn
Room
stat
Cyl
stat
CH Zone v
alv
e
DHW Zone v
alv
e
NO
C
br
br
b
b
g/y
g/y
Pump
supplied
from
boiler
N
NC
T
ypical System
Wiring - tw
o zone v
alves (S Plan)
Exter
nal Prog
rammer
The Pump can be wired through the wir
ing centre
b
ut m
ust be wired direct to Pump L, N & Ear
th
on boiler ter
minal b
loc
k.
b - b
lue
br - bro
wn
g/y - g
reen y
ello
w
Boiler PCB