Bosch WORCESTER GREENSTAR WIRING CENTRE, Installation, Commissioning & Servicing Instructions

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INSTALLATION
6 720 804 107 (2012/10) 9
MID-POSITION (Y-PLAN) SYSTEM:
Fig. 20 Mid-position system
Earth conductor
L Phase (230 V AC)
N Neutral conductor
Switches:
I Code switch I – system type
II Temperature switch II – domestic hot water cylinder
temperature
Terminal identification:
230 V AC Mains voltage
BUS
BUS EMS plus
IZ1 No function
IZ2 No function
IZ3 Room thermostat ( I nput Z one;

: Temperature/temperature
sensor)
IZ4 Frost thermostat (

: Temperature/temperature sensor)
MD1 No function
OS1 No function
PZ1...2 Mid-position valve:
terminal 14: DHW off
terminal 43: heating mode
PZ3 Circulating pump ( P ump Z one)
T0 No function
T1 No function
TC1 Cylinder temperature sensor ( T emperature sensor C ylinder)
System component:
230 V AC Mains voltage
BUS
BUS EMS plus (connection between the Greenstar Wiring
Centre and boiler)
GWC Greenstar Wiring Centre
HS Boiler ( H eat S ource)
PHS Circulating pump ( P ump H eat S ource)
TC1 Cylinder temperature sensor ( T emperature sensor C ylinder)
TR3 Room thermostat ( T hermostat R oom temperature); optional;
not shown in fig. 20
TF4 Frost thermostat ( T hermostat F rost protection); optional; not
shown in fig. 20
VZ12 Diverter valve ( V alve Z one); connect as follows:
green/yellow to: PZ1 –
blue to: PZ1 – N
grey to: PZ1 – 14
white to: PZ2 – 43
orange to: PZ2 – no lettering (no function)
0
1
2
3
4
S
Y
I
off off
40 40
50 50 60 60
70 70
max max
II II
GWC
PHS
TC1
VZ12
HS
6 720 804 107-18.1O
1 2 1 2 1 2
TC1 T0 BUS BUS
1 2
BUS
1 2 3 1
OS1
2 1 2
MD1
1 2
T1
≤ 24 V
N L N L N IN L IN L IN L IN L
120/230VAC 120/230VAC
IZ1 IZ2 IZ3 IZ4
120/230 V AC
N N 43 N 14 14
PZ2 PZ3 PZ1
120/230 V AC
230 V AC 230 V AC
L N L N
BUS TC1
VZ12
M
N
M
N 1 2
5
14 43
N
M
PHS
N L
L N
TR3
L S
TF4
L S