Bosch WORCESTER GREENSTAR - Two-port valve (S-plan) system; System components:; Terminal identification:

Installation
GREENSTAR WIRING CENTRE – 6720880441 (2018/01)
12
Two-port valve (S-plan) system:
Fig. 23 Two-port valve system
Earth lead
L Phase (mains voltage)
N Neutral conductor
Switch:
I Code switch I – system type
II Temperature switch II – domestic hot water cylinder
temperature
Terminal identification:
230 V AC Mains voltage
BUS EMS 2 BUS
IZ1 DHW two-port valve end switch
IZ2 Central heating two-port valve limit switch
IZ3 Room thermostat
(Input Zone; : temperature/temperature sensor)
IZ4 Frost stat (: temperature/temperature sensor)
MD1 No function
OS1 No function
PZ1 DHW two-port valve motor
PZ2 Central heating two-port valve motor
PZ3 DHW circulation pump (Pump Zone)
T0 No function
T1 No function
TC1 Cylinder temperature sensor (Temperature sensor Cylinder)
System components:
230 V AC Mains voltage
BUS EMS 2 BUS
(connection between Greenstar Wiring Centre and boiler)
CZ1 Two-port valve limit switch, valve switch for DHW
(Contact Zone)
CZ2 Two-port valve limit switch, valve switch for heating
(Contact Zone)
GWC Greenstar Wiring Centre
HS Boiler (Heat Source)
PHS Domestic hot water circulation pump (Pump Heat Source)
TC1 Cylinder temperature sensor (Temperature sensor Cylinder)
TR3 Room thermostat (Thermostat Room temperature); optional;
not shown in Fig. 21
TF4 Frost stat (Thermostat Frost protection); optional; not shown
in Fig. 21
VZ1 Two-port valve for DHW (Valve Zone)
VZ2 Two-port valve for heating (Valve Zone)
When there is a simultaneous demand for central heating and domestic
hot water, the S-plan diverter valve will operate for 10 minutes at a time
between both until both demands have been met. To reduce extended
heat-up times for central heating and hot water, it is recommended to
adjust the program to meet the demand for hot water before the central
heating demand is started
HS
GWC
PHS
TC1
VZ1
CZ1
VZ2
CZ2
0010016318-001
1212 12
TC1 T0
BUS
BUS
12
BUS
123 1
OS1
212
MD1
12
T1
24 V
NL N LN IN L IN L IN L INL
120/230VAC 120/230VAC
IZ1 IZ2 IZ3 IZ4
120/230 V AC
NN43N1414
PZ2 PZ3PZ1
120/230 V AC
230 V AC 230 V AC
L
N
L
N
BUS
TC1
M
VZ1
NL
LN
N
M
VZ2
NL
L
M
PHS
NL
LN
CZ1 CZ2 TR3
LS
TF4
LS
I
II
II
0
1
2
3
4
S
Y
off
off
40
40
50
50
60
60
70
70
max
max