Worcester wiring guide
Greenstar gas-fired boilers
Contents
Introduction
Page 4
Greenstar Ri Regular
Page 5
Greenstar CDi Regular
Page 17
Greenstar CDi System
Page 29
Greenstar CDi Combi
Page 42
Greenstar FS CDi Regular
Page 53
Greenstar HF CDi Combi
Page 65
Greenstar Si Combi
Page 71
Greenstar i Junior Combi
Page 82
Greenstar i System
Page 93
Notes
Worcester wiring guide Greenstar gas-fired boilers
Page 105
Page 3
Introduction
NEW COMPLETE SYSTEM INSTALLATIONS
If a new complete heating system installation is in a new build property or it is
a first time installation in an existing property, then the heating system must
conform to current building regulations Part L1a. All new heating systems in
dwellings must have at least two heating zones. Each of these zones will be
controlled by a thermostat and zone valve. An alternative would be individual
electronically controlled TRVs. If the hot water is provided from a storage
system then the DHW cylinder will require separate time and temperature
control. All radiators must have TRVs fitted in all rooms except bathrooms and
rooms with thermostats. The exception to this are single storey, open plan
dwellings where the living area is more than 70% of the total useable floor
area. Then this type of dwelling can be controlled as one zone.
EXISTING INSTALLATIONS
For boiler replacements on an existing system, it is not necessary to zone the
upstairs and downstairs differently, compliance with the zone requirements
can be achieved by a single room thermostat or programmable room
thermostat. While the system is drained down, TRVs may be fitted to all
rooms except the bathrooms and the room with the thermostat.
Page 4
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
2 x 2 Port Valves (S-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
L
N
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room
T/Stat
LP NP LR
E
reset
L
Cylinder
T/Stat
N
230V Mains
Voltage
Double Pole
Fused Spur
~
N
Heating
Zone Valve
max
C
1
2
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
External
Pump
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 5
Greenstar Ri Regular
Mid Position Valve (Y-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
= Live
L
L
N
N = Neutral
E
E
= Earth
Mid Position
Valve
N
L
N
Room
T/Stat
LP NP LR
reset
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
230V Mains
Voltage
Double Pole
Fused Spur
E
C
max
1
2
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
HW OFF
CH ON
External
Pump
HW ON
L
N
E
N
L
Time Controller
Page 6
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
3 x 2 Port Valves (S-Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
L
N
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
LP NP LR
E
reset
L
Cylinder
T/Stat
N
230V Mains
Voltage
Double Pole
Fused Spur
~
N
Heating
Zone 1 Valve
max
C
1
2
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
CH Zone 1 ON
HW ON
M
CH Zone 2 ON
External
Pump
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 7
Greenstar Ri Regular
2 x Radiator Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
L
N
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
LP NP LR
reset
E
Room T/Stat
Zone 2
N
230V Mains
Voltage
Double Pole
Fused Spur
~
N
Heating
Zone 1 Valve
N
max
L
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
CH Zone 2 ON
External
Pump
CH Zone 1 ON
L
N
E
N
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Page 8
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
L
N
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
LP NP LR
E
reset
L
Cylinder
T/Stat
N
230V Mains
Voltage
Double Pole
Fused Spur
~
N
Heating
Zone 1 Valve
max
C
2
1
L
N
E
E
L
N
E
L
N
E
External
Pump
4
5
6
7
8
9
10
M
~
N
HW ON
N
CH Zone 1 ON
L
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controler
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 9
Greenstar Ri Regular
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
= Earth
E
Greenstar
Ri Regular
L
N
LP NP LR
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Radiators Zone
~
N
E
L
N
230V Mains
Voltage
Double Pole
Fused Spur
reset
Radiators
Zone Valve
max
L
N
E
L
N
E
L
N
E
L
N
E
4
5
6
External
Pump
N
L
Time Controller
Single Channel
Page 10
7
8
9
10
L
N
E
L
N
E
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
Single Hot Water Zone (Vented Cylinder)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
= Live
L
L
N
N = Neutral
E
E
= Earth
Cylinder
T/Stat
C
L
N
LP NP LR
2
1
230V Mains
Voltage
Double Pole
Fused Spur
reset
max
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
External
Pump
N
L
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Page 11
Greenstar Ri Regular
Single Heating Zone
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
= Live
L
L
N
N = Neutral
E
E
= Earth
Room
T/Stat
N
L
N
230V Mains
Voltage
Double Pole
Fused Spur
LP NP LR
reset
max
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
External
Pump
N
L
Time Controller
Single Channel
Page 12
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
Grundfoss Pump Plan
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
IMPORTANT NOTE
The pump over-run of the pump plan module, causes the hot water pump to run regardless of the
hot water cylinder demand, to dissipate boiler heat. Worcester will only recommend the
Grundfoss pump plan system on a vented cylinder.
Greenstar
Ri Regular
230V Mains
Voltage
Double Pole
Fused Spur
L
N
LP NP LR
Warning! 240V - Isolate electrical supply
before removing wiring centre cover.
reset
L
N
E
max
2.5A Fuse - RS Components stock no 415-604
BOILER
FUSE
2.5A
N
L
N
L
S/L
1
Frost T/Stat
FROST T/STAT
(if required)
(N/U)
2
C
(N/U)
NO
Demand
N
L
NO
N
d
an
em
C
D
2
De
m
an
d
(N/U)
1
Cylinder
T/Stat
CYLINDER
T/STAT
C
(N/U)
L
L
N
ROOM T/STAT
Room T/Stat
P/L
N
N
NO
1
HW PUMP
HW Pump
N
L
CH PUMP
CHPump
N
CH on
HW on
N
L
CH on
PROGRAMMER
HW on
4
(N/U)
(N/U)
CH/HW
Programmer
3
Earth terminal for:
Controls, Boiler, Pumps
Electrical Mains Supply
(N/U)
2
L
N/U = Not Used
UPP 15-50 PUMP PLAN - WIRING CENTRE CONNECTIONS
Worcester wiring guide Greenstar gas-fired boilers
Page 13
Greenstar Ri Regular
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
Ri Regular
L
230V Mains
Voltage
Double Pole
Fused Spur
N
SMARTFIT
ROOM UNIT
LP NP LR
reset
Smartfit Layout:
Example shown S Plan configuration
max
MAINS
BOILER
L
N
E
PUMP
L
N
E
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
L
SL
POLARITY
FREE
Y PLAN
S PLAN
PL
N
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
ACCESSORY
PORT
CYLINDER
SENSOR
External
Pump
HW VALVE (S)
CH VALVE (S)
Page 14
CYLINDER
T/STAT
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Ri Regular
Cascaded boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
= Earth
E
NOTE
A pump must be wired to each boiler for pump over-run to dissipate heat from within the boiler.
The connections are Live of pump to LP and Neutral of pump to NP and the Earth of the pump to
the Earth point of each boiler.
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90º C.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
NO
NC
NC
C
Header Limit
Thermostat
C
N
O
N
C
L
230V Mains
Voltage
Double Pole
Fused Spur
N
C
Greenstar
Ri Regular
LP NP LR
reset
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
230V AC
Double Pole Relay
C
Greenstar
Ri Regular
NO
L
max
N
LP NP LR
reset
max
L
N
E
L
N
E
Shunt
Pump
Worcester wiring guide Greenstar gas-fired boilers
L
N
E
Shunt
Pump
Page 15
Greenstar Ri Regular
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
NOTE
A frost thermostat is normally used to protect locations which have no heat source e.g. a garage.
It is recommended that a pipe thermostat is also used (wired in series with the frost thermostat)
to avoid long periods of heat demand if the air temperature does not satisfy the frost thermostat.
Frost T/Stat
Pipe T/Stat
Greenstar
Ri Regular
L
N
reset
L
N = Neutral
E
E
= Earth
Room
T/Stat
LP NP LR
Cylinder
T/Stat
N
230V Mains
Voltage
Double Pole
Fused Spur
= Live
L
N
Heating
Zone Valve
max
C
1
2
L
N
E
E
L
N
E
4
L
N
E
5
6
7
8
9
10
HW ON
N
CH ON
L
N
External
Pump
L
Time Controller
Page 16
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
2 x 2 Port Valves (S-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
Greenstar
CDi Regular
E
= Earth
Room
T/Stat
M
N
E
LZ NZ
L
~
N
L
Cylinder
T/Stat
Heating
Zone Valve
C
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
L
N
E
~
N
E
L
E
N
External
Pump
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 17
Greenstar CDi Regular
Mid Position Valve (Y-plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Mid Position
Valve
Room
T/Stat
Greenstar
CDi Regular
N
N
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
LZ NZ
C
L
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
4
5
6
7
2
8
9
10
External
Pump
HW OFF
E
HW ON
L
N
E
CH ON
L
N
E
N
L
Time Controller
Page 18
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
3 x 2 Port Valves (S-Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Regular
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
LZ NZ
L
~
N
N
E
Cylinder
T/Stat
Heating
Zone 1 Valve
C
N NS LS LR
1
L
2
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
4
5
6
7
L
N
E
External
Pump
CH Zone 1 ON
E
HW ON
8
9
10
M
CH Zone 2 ON
L
N
E
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 19
Greenstar CDi Regular
2 x Radiator Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Regular
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
N
LZ NZ
E
Room T/Stat
Zone 2
N NS LS LR
L
N
E
N
E
L
N
E
4
5
6
CH Zone 2 ON
L
N
E
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
7
8
9
10
M
~
N
E
L
E
N
External
Pump
L
Heating
Zone 1 Valve
N
L
~
N
Heating
Zone 2 Valve
L
Time Controller
Page 20
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Regular
L
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
~
N
N
LZ NZ
L
= Live
L
N
E
Cylinder
T/Stat
L
Heating
Zone 1 Valve
C
N NS LS LR
2
1
N
E
L
N
E
L
N
E
L
N
E
4
5
6
8
9
10
M
~
N
E
E
L
Cylinder
Zone Valve
N
External
Pump
7
HW ON
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 21
Greenstar CDi Regular
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
Greenstar
CDi Regular
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/stat
Radiators Zone
M
N
E
LZ NZ
L
~
N
L
Radiators
Zone Valve
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
L
N
E
External
Pump
Page 22
E
N
L
Time Controller
Single Channel
L
N
E
L
N
E
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
Single Hot Water Zone (Vented Cylinder)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Cylinder
T/Stat
Greenstar
CDi Regular
C
L
2
1
LZ NZ
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
L
N
E
N
E
L
External
Pump
Worcester wiring guide Greenstar gas-fired boilers
Time Controller
Single Channel
Page 23
Greenstar CDi Regular
Single Heating Zone
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room
T/Stat
Greenstar
CDi Regular
N
LZ NZ
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
L
N
E
N
E
L
External
Pump
Page 24
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
Grundfoss Pump Plan
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
= Earth
E
IMPORTANT NOTE
The pump over-run of the pump plan controls, causes the hot water pump to run regardless of the
hot water cylinder demand, to dissipate boiler heat. Worcester would only recommend the
Grundfoss pump plan system on a vented cylinder.
Greenstar
CDi Regular
LZ NZ
N NS LS LR
L
230V Mains
Voltage
Double Pole
Fused Spur
Warning! 240V - Isolate electrical supply
before removing wiring centre cover.
L
N
E
2.5A Fuse - RS Components stock no 415-604
BOILER
FUSE
2.5A
N
L
N
L
S/L
1
Frost T/Stat
FROST T/STAT
(if required)
(N/U)
2
C
(N/U)
NO
Demand
D
em
an
d
2
N
NO
N
C
De
m
an
d
(N/U)
1
Cylinder
T/Stat
CYLINDER
T/STAT
C
(N/U)
L
L
N
L
ROOM T/STAT
Room T/Stat
P/L
N
N
NO
1
HW PUMP
HW Pump
N
L
CH PUMP
CHPump
N
CH on
HW on
N
L
CH on
PROGRAMMER
HW on
4
(N/U)
(N/U)
CH/HW
Programmer
3
Earth terminal for:
Controls, Boiler, Pumps
Electrical Mains Supply
(N/U)
2
L
N/U = Not Used
UPP 15-50 PUMP PLAN - WIRING CENTRE CONNECTIONS
Worcester wiring guide Greenstar gas-fired boilers
Page 25
Greenstar CDi Regular
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar
CDi Regular
LZ NZ
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
Smartfit Layout:
Example shown S Plan configuration
MAINS
L
N
E
BOILER
PUMP
L
N
E
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
L
SL
Y PLAN
S PLAN
PL
N
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
POLARITY
FREE
ACCESSORY
PORT
CYLINDER
SENSOR
External
Pump
HW VALVE (S)
CH VALVE (S)
Page 26
CYLINDER
T/STAT
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Regular
Cascaded boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
NOTE
A pump must be wired to each boiler for pump over-run function to dissipate heat from within the
boiler. The connections are pump live to Lz, pump neutral to Nz and pump earth to the Earth
point of each boiler.
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90ºC.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The relay should be mounted within
a suitable electrically safe housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
NO
NC
NC
C
Header Limit
Thermostat
C
N
O
N
C
230V AC
Double Pole Relay
C
C
Coil
Coil
Live
Neutral
Example relay shown is a double
pole mains voltage relay. This
isolates the boilers electrically in
case of a fault condition.
C
Greenstar
CDi Regular
Greenstar
CDi Regular
LZ NZ
L
NO
N NS LS LR
LZ NZ
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
Shunt
Pump
Worcester wiring guide Greenstar gas-fired boilers
L
N
E
Shunt
Pump
Page 27
Greenstar CDi Regular
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
CDi Regular
FR FS NP LP
LZ NZ
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
Earth to Wiring Centre
Neutral Feed to Wiring Centre
Live Feed to Wiring Centre
Switch Live from Wiring Centre
L
N
E
L
N
E
External
Pump
Page 28
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
2 x 2 Port Valves (S-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
L
N
N = Neutral
E
Room
T/Stat
Greenstar
CDi System
= Live
L
E
= Earth
M
~
N
N
E
L
Cylinder
T/Stat
L
Heating
Zone Valve
C
N NS LS LR
1
2
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 29
Greenstar CDi System
Mid Position Valve (Y-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi System
= Live
L
L
N
N = Neutral
E
E
Mid Position
Valve
= Earth
Room
T/Stat
N
N
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
C
L
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
1
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW OFF
HW ON
CH ON
L
N
E
N
L
Time Controller
Page 30
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
3 x 2 Port Valves (S-Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi System
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
~
N
N
E
L
Cylinder
T/Stat
L
Heating
Zone 1 Valve
C
N NS LS LR
1
L
N
E
L
N
E
L
N
E
4
CH Zone 1 ON
HW ON
5
6
7
8
9
10
M
CH Zone 2 ON
230V Mains
Voltage
Double Pole
Fused Spur
2
~
N
E
L
Cylinder
Zone Valve
N
M
N
L
E
Time Controller
3 Channel
N
~
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 31
Greenstar CDi System
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi System
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
N
E
Room T/Stat
Zone 2
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
L
N
E
L
N
E
4
5
6
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
CH Zone 2 ON
CH Zone 1 ON
L
N
E
N
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Page 32
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi System
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
E
N
L
Heating
Zone 1 Valve
C
N NS LS LR
2
N
E
L
N
E
4
5
6
7
8
9
10
M
~
N
HW ON
L
CH Zone 1 ON
L
N
E
L
Cylinder
T/Stat
1
230V Mains
Voltage
Double Pole
Fused Spur
~
N
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 33
Greenstar CDi System
Zoned Radiator & Underfloor
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar
CDi System
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Radiators Zone
M
E
N
L
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
Radiators
Zone Valve
N NS LS LR
L
N
E
L
N
E
4
5
6
N
L
Time Controller
Single Channel
Page 34
~
N
7
8
9
10
L
N
E
L
N
E
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
Single Hot Water Zone (Vented Cylinder)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Cylinder
T/Stat
Greenstar
CDi System
C
2
1
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Page 35
Greenstar CDi System
Single Heating Zone
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room
T/Stat
Greenstar
CDi System
N
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
Time Controller
Single Channel
Page 36
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi System
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
MAINS
L
N
E
Smartfit Layout:
Example shown S Plan configuration
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
BOILER
L
SL
Y PLAN
S PLAN
PL
N
PUMP
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
POLARITY
FREE
ACCESSORY
PORT
CYLINDER
SENSOR
HW VALVE (S)
CH VALVE (S)
Worcester wiring guide Greenstar gas-fired boilers
CYLINDER
T/STAT
Page 37
Greenstar CDi System
Internal Diverter Valve, Worcester RF Controls & Unvented Cylinder
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
= Earth
E
There is a unclarity within the Industry that in order to protect an Unvented Hot Water Cylinder from potentially
dangerous high temperatures from the boiler circuit, a 2-port motorised valve must be installed. This is not the
case, although it is the most common interpretation and approach.
FURTHER DETAILS
Building Regulation Approved Document G3, paragraph 3.6 states '…the non-self-resetting thermal cut out
should be wired to a motorised valve or some other suitable device to shut off the flow to the primary heater…'.
The latter part of this sentence can be interpreted to mean as long as we, as responsible Manufacturer's, are
confident our method provides an equal amount of protection to the common approach, we may instruct
installers of our equipment to follow a different approach. A summary is provided below.
G
The installer will use the cylinder sensor supplied with the Integral Diverter Valve kit to control the hot water
temperature.
G
The installer, therefore, will NOT need to use the hot water control thermostat of the cylinder's dual thermostat.
G
The installer may have to alter the wiring of the dual thermostat (depending on cylinder and thermostat
manufacturer) to only use the high limit thermal cut-out of the dual thermostat.
G
The high limit thermal cut out of the dual thermostat MUST be wired to interrupt the permanent live to the
Greenstar CDi System Boiler.
G
The 2-port valve supplied with the unvented cylinder will NOT be used. If it is already physically installed in
the pipe work is should be removed and electrically disconnected from the wiring centre.
Below you will find an electrical diagram for this arrangement.
DUAL THERMOSTAT
230V MAINS
SUPPLY
SAFETY LIMIT
THERMOSTAT
CYLINDER
THERMOSTAT
Connector
Block
Green\Yellow
(made safe)
NOT REQUIRED
USE CYLINDER SENSOR SUPPLIED
IMPORTANT NOTE:
UNDER NO CIRCUMSTANCES SHOULD THE FEED TO THE LIMIT
STAT BE TAKEN THROUGH THE CONTROL STAT.
Brown
Blue
Brown
N E L
ST8
9
8
L
FR FS NP LP
ST10
ST6
Pump
Harness
Fan
Harness
FR FS NP LP
L
N NS LS LR
9
ST19
B
B
4
2
1
A
F
B
B
4
2
1
A
F
CYLINDER TEMPERATURE
SENSOR (SUPPLIED IN
8
7
S11
2.5 A 230 V AC
NOTE:
Leave link
7
NOTE:
Leave link
LR LS NS N
DIVERTER KIT)
Main
Harness
DIVERTER VALVE
MOTOR PLUG
S12
0.5 A
S13
1.6 A
Pump Control
Code Plug
Page 38
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
Internal Diverter Valve, Worcester FX Controls & Unvented Cylinder
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
= Earth
E
There is a unclarity within the Industry that in order to protect an Unvented Hot Water Cylinder from potentially
dangerous high temperatures from the boiler circuit, a 2-port motorised valve must be installed. This is not the
case, although it is the most common interpretation and approach.
FURTHER DETAILS
Building Regulation Approved Document G3, paragraph 3.6 states '…the non-self-resetting thermal cut out
should be wired to a motorised valve or some other suitable device to shut off the flow to the primary heater…'.
The latter part of this sentence can be interpreted to mean as long as we, as responsible Manufacturer's, are
confident our method provides an equal amount of protection to the common approach, we may instruct
installers of our equipment to follow a different approach. A summary is provided below.
G
The installer will use the cylinder sensor supplied with the Integral Diverter Valve kit to control the hot water
temperature.
G
The installer, therefore, will NOT need to use the hot water control thermostat of the cylinder's dual thermostat.
G
The installer may have to alter the wiring of the dual thermostat (depending on cylinder and thermostat
manufacturer) to only use the high limit thermal cut-out of the dual thermostat.
G
The high limit thermal cut out of the dual thermostat MUST be wired to interrupt the permanent live to the
Greenstar CDi System Boiler.
G
The 2-port valve supplied with the unvented cylinder will NOT be used. If it is already physically installed in
the pipe work is should be removed and electrically disconnected from the wiring centre.
Below you will find an electrical diagram for this arrangement.
DUAL THERMOSTAT
230V MAINS
SUPPLY
SAFETY LIMIT
THERMOSTAT
CYLINDER
THERMOSTAT
Connector
Block
Green\Yellow
(made safe)
NOT REQUIRED
USE CYLINDER SENSOR SUPPLIED
IMPORTANT NOTE:
UNDER NO CIRCUMSTANCES SHOULD THE FEED TO THE LIMIT
STAT BE TAKEN THROUGH THE CONTROL STAT.
Brown
Blue
Brown
N E L
ST8
9
8
L
FR FS NP LP
ST10
ST6
Pump
Harness
9
Fan
Harness
FR FS NP LP
ST19
B FW 100
B CONTROLLER
B
B
4
2
1
A
F
B
B
4
2
1
A
F
A OUTSIDE
F SENSOR
CYLINDER TEMPERATURE
SENSOR (SUPPLIED IN
8
7
L
N NS LS LR
S11
2.5 A 230 V AC
NOTE:
Leave link
7
NOTE:
Leave link
LR LS NS N
DIVERTER KIT)
Main
Harness
DIVERTER VALVE
MOTOR PLUG
S12
0.5 A
S13
1.6 A
Pump Control
Code Plug
Worcester wiring guide Greenstar gas-fired boilers
Page 39
Greenstar CDi System
Cascaded boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90º C.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
N
C
230V AC
Double Pole Relay
C
N NS LS LR
NC
NO
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
C
Greenstar
CDi System
L
NC
C
Header Limit
Thermostat
C
N
O
NO
Greenstar
CDi System
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 40
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi System
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
CDi System
FR FS NP LP
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
Earth to Wiring Centre
Neutral Feed to Wiring Centre
Live Feed to Wiring Centre
Switch Live from Wiring Centre
Page 41
Greenstar CDi Combi
2 x 2 Port Valves (S-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
M
Room
T/Stat
E
L
N
E
Heating
Zone Valve
C
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Page 42
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Combi
Mid Position Valve (Y-Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
Mid Position
Valve
N
Room
T/Stat
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
C
L
N
E
L
N
E
4
CH ON
L
N
E
1
5
6
7
2
8
9
10
HW OFF
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
HW ON
L
N
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 43
Greenstar CDi combi
3 x 2 Port Valves (S-Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
~
N
E
Heating
Zone 1 Valve
C
N NS LS LR
1
L
N
E
L
N
E
L
N
E
4
5
6
7
2
8
CH Zone 1 ON
HW ON
9
10
M
CH Zone 2 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
= Live
L
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Page 44
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi combi
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
M
Room T/Stat
Zone 1
E
Room T/Stat
Zone 2
N
L
N
E
L
N
E
4
5
6
CH Zone 2 ON
L
N
E
N NS LS LR
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
N
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 45
Greenstar CDi Combi
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
M
~
N
N
E
L
Cylinder
T/Stat
L
2
1
N
E
L
N
E
4
5
6
7
8
9
10
M
~
N
HW ON
L
N
E
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
Heating
Zone 1 Valve
C
N NS LS LR
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Page 46
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Combi
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar
CDi Combi
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Radiators Zone
N
M
~
N
E
L
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
Radiators
Zone Valve
N NS LS LR
L
N
E
L
N
E
4
5
6
7
8
9
10
L
N
E
L
N
E
N
L
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Demand
Underfloor Controls
Wiring Centre
Page 47
Greenstar CDi Combi
separate Time Controller & Room Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Series Connector
Not supplied. Once wired in make
connector safe in electrical cover.
Greenstar
CDi Combi
L
Room
T/Stat
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Time Controller
Page 48
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Combi
Programmable Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
Programmable
Thermostat
L
N NS LS LR
N
L
C NC NO
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
The Link between the Live (L) and
Common (C) may already be fitted as
part of the Programmable Thermostat, if
not then a link must be fitted.
Page 49
Greenstar CDi Combi
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
CDi Combi
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
MAINS
L
N
E
Smartfit Layout:
Example shown S Plan configuration
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
BOILER
L
SL
Y PLAN
S PLAN
PL
N
PUMP
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
POLARITY
FREE
ACCESSORY
PORT
CYLINDER
SENSOR
HW VALVE (S)
CH VALVE (S)
Page 50
CYLINDER
T/STAT
Worcester wiring guide Greenstar gas-fired boilers
Greenstar CDi Combi
Cascade boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
NOTE
A pump must be wired to each boiler for pump over-run to dissipate heat from within the boiler.
The connections are pump live to Lz, pump neutral to Nz and pump earth to the Earth point of
each boiler.
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90ºC.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
NO
NC
C
Header Limit
Thermostat
C
N
O
N
C
230V AC
Double Pole Relay
C
N NS LS LR
NO
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
C
Greenstar
CDi Combi
L
NC
Greenstar
CDi Combi
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
Page 51
Greenstar CDi Combi
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
CDi Combi
FR FS NP LP
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 52
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
2 x 2 Port Valves (S Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
Greenstar FS
CDi Regular
L
E
= Earth
= Live
L
L
N
N = Neutral
E
E
N NS LS LR
= Earth
Room
T/Stat
N
LZ NZ
M
~
N
E
L
Cylinder
T/Stat
Heating
Zone Valve
C
1
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
L
N
E
N
External
Pump
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 53
Greenstar FS CDi Regular
Mid Position Valve (Y Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
Greenstar FS
CDi Regular
L
N NS LS LR
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Mid Position
Valve
N
LZ NZ
Room
T/Stat
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
C
1
N
E
L
N
E
L
N
E
External
Pump
CH ON
L
N
E
4
5
6
7
8
9
10
HW OFF
L
HW ON
230V Mains
Voltage
Double Pole
Fused Spur
2
N
L
Time Controller
Page 54
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
3 x 2 Port Valves (S Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar FS
CDi Regular
L
= Live
L
L
N
N = Neutral
E
E
= Earth
N NS LS LR
LZ NZ
M
Room T/Stat
Zone 1
E
L
Cylinder
T/Stat
N
Heating
Zone 1 Valve
C
1
230V Mains
Voltage
Double Pole
Fused Spur
~
N
L
N
E
L
N
E
4
5
6
7
2
8
9
10
L
N
E
External
Pump
CH Zone 1 ON
HW ON
CH Zone 2 ON
L
N
E
M
~
N
E
L
Cylinder
Zone Valve
N
M
N
L
E
Time Controller
3 Channel
N
~
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 55
Greenstar FS CDi Regular
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar FS
CDi Regular
L
N NS LS LR
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
LZ NZ
M
Room T/Stat
Zone 1
E
Room T/Stat
Zone 2
N
E
L
N
E
L
N
E
4
5
6
CH Zone 2 ON
N
CH Zone 1 ON
L
N
E
L
N
External
Pump
L
Heating
Zone 1 Valve
N
230V Mains
Voltage
Double Pole
Fused Spur
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Page 56
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar FS
CDi Regular
L
N NS LS LR
= Live
L
L
N
N = Neutral
E
E
= Earth
LZ NZ
M
Room T/Stat
Zone 1
~
N
E
L
Cylinder
T/Stat
N
Heating
Zone 1 Valve
C
2
1
N
E
L
N
E
L
N
E
4
5
6
8
9
10
M
~
N
E
L
Cylinder
Zone Valve
N
External
Pump
7
HW ON
L
N
E
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 57
Greenstar FS CDi Regular
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar FS
CDi Regular
L
N NS LS LR
= Live
L
L
N
N = Neutral
E
E
= Earth
LZ NZ
M
Room T/Stat
Radiators Zone
~
N
E
L
N
Radiators
Zone Valve
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
External
Pump
Page 58
L
N
E
L
N
E
4
5
6
N
L
Time Controller
Single Channel
7
8
9
10
L
N
E
L
N
E
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
Single Hot Water Zone (Vented Cylinder)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar FS
CDi Regular
L
= Live
L
L
N
N = Neutral
E
E
= Earth
N NS LS LR
Cylinder
T/Stat
LZ NZ
C
2
1
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
External
Pump
Worcester wiring guide Greenstar gas-fired boilers
Time Controller
Single Channel
Page 59
Greenstar FS CDi Regular
Single Heating Zone
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Greenstar FS
CDi Regular
L
N NS LS LR
= Live
L
L
N
N = Neutral
E
E
= Earth
Room
T/Stat
LZ NZ
N
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
External
Pump
Page 60
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
Grundfoss Pump Plan
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
IMPORTANT NOTE
The pump over-run of the pump plan controls, causes the hot water pump to run regardless of the
hot water cylinder demand, to dissipate boiler heat. Worcester would only recommend the
Grundfoss pump plan system on a vented cylinder.
Greenstar FS
CDi Regular
N NS LS LR
L
LZ NZ
230V Mains
Voltage
Double Pole
Fused Spur
Warning! 240V - Isolate electrical supply
before removing wiring centre cover.
L
N
E
2.5A Fuse - RS Components stock no 415-604
BOILER
FUSE
2.5A
N
L
N
L
S/L
1
Frost T/Stat
FROST T/STAT (N/U)
(if required)
(N/U)
2
Demand
N
L
NO
N
an
d
em
C
m
an
d
(N/U)
De
1
Cylinder T/Stat
CYLINDER
T/STAT
C
(N/U)
L
L
N
D
2
P/L
N
NO
ROOM T/STAT
Room T/Stat
C
N
NO
HW PUMP
HW Pump
N
L
CH PUMP
CHPump
N
CH on
HW on
N
L
CH on
PROGRAMMER
HW on
4
(N/U)
(N/U)
CH/HW
Programmer
3
1
(N/U)
2
L
N/U = Not Used
UPP 15-50 PUMP PLAN - WIRING CENTRE CONNECTIONS
Worcester wiring guide Greenstar gas-fired boilers
Page 61
Greenstar FS CDi Regular
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar FS
CDi Regular
L
N NS LS LR
LZ NZ
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
Smartfit Layout:
Example shown S Plan configuration
MAINS
L
N
E
BOILER
PUMP
L
N
E
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
L
SL
S PLAN
POLARITY
FREE
Y PLAN
PL
N
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
ACCESSORY
PORT
CYLINDER
SENSOR
External
Pump
HW VALVE (S)
CH VALVE (S)
Page 62
CYLINDER
T/STAT
Worcester wiring guide Greenstar gas-fired boilers
Greenstar FS CDi Regular
Cascaded boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
NOTE
A pump must be wired to each boiler for pump over-run to dissipate heat from within the boiler.
The connections are pump live to Lz, pump neutral to Nz and pump earth to the Earth point of
each boiler.
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90ºC.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
NO
NC
NC
E
C
C
Coil
Live
Header Limit
Thermostat
C
Greenstar FS
CDi Regular
L
NO
Switched Live/
Demand
N
O
N
C
230V AC
Double Pole Relay
C
N NS LS LR
C
Coil
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
Greenstar FS
CDi Regular
L
N NS LS LR
LZ NZ
LZ NZ
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
Shunt
Pump
Worcester wiring guide Greenstar gas-fired boilers
L
N
E
Shunt
Pump
Page 63
Greenstar FS CDi Regular
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Greenstar FS
CDi Regular
230V Mains
Voltage
L
= Live
L
L
N
N = Neutral
E
E
= Earth
N NS LS LR
LZ NZ
Double Pole
Fused Spur
Earth to Wiring Centre
L
N
E
Neutral Feed to Wiring Centre
Live Feed to Wiring Centre
Switch Live from Wiring Centre
FR FS NP LP
Frost Stat
L
N
E
E
External
Pump
Page 64
Worcester wiring guide Greenstar gas-fired boilers
Greenstar HF CDi combi
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
= Earth
E
230V Mains
Voltage
Double Pole
Fused Spur
Greenstar HF CDi
L
N NS LS LR
= Live
L
L
N
N = Neutral
E
E
= Earth
L
N
E
230V HW interface
‘Installer Module’
M
Room T/Stat
Zone 1
Safety isolation
N
E
Room T/Stat
Zone 2
N
NC
L
N
E
HW ON
4
5
6
CH Zone 2 ON
E
CH Zone 1 ON
N
N
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
3 Channel
Worcester wiring guide Greenstar gas-fired boilers
Page 65
Greenstar HF CDi combi
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
230V Mains
Voltage
Double Pole
Fused Spur
Greenstar HF CDi
L
N NS LS LR
= Live
L
L
N
N = Neutral
E
E
= Earth
L
N
E
230V HW interface
‘Installer Module’
M
Room T/Stat
Radiators Zone
Safety isolation
N
~
N
E
L
N
NC
Radiators
Zone Valve
N
E
L
N
E
4
5
CH Rads ON
HW Heat Bank ON
L
N
6
7
8
9
10
L
N
E
L
N
E
Demand
Underfloor Controls
Wiring Centre
L
Time Controller
Page 66
Worcester wiring guide Greenstar gas-fired boilers
Greenstar HF CDi combi
separate Time Controller & Room Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
230V Mains
Voltage
Double Pole
Fused Spur
E
E
= Earth
Greenstar HF CDi
L
N NS LS LR
L
N
E
Room T/Stat
230V HW interface
‘Installer Module’
Safety isolation
N
Series Connector
Not supplied. Once wired in make
connector safe in electrical cover.
HW Heat Bank ON
CH ON
NC
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 67
Greenstar HF CDi combi
Programmable Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Programmable
Thermostat
230V Mains
Voltage
Double Pole
Fused Spur
Greenstar HF CDi
L
N NS LS LR
N
L
C NC NO
L
N
E
230V HW interface
‘Installer Module’
Safety isolation
N
HW Heat Bank ON
NC
The Link between the Live (L) and
Common (C) may already be fitted as
part of the Programmable Thermostat, if
not then a link must be wired in.
Time Controller
Hot Water
Heat Bank
Page 68
Worcester wiring guide Greenstar gas-fired boilers
Greenstar HF CDi combi
Large heating circuit with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
If the heating system requires a larger pump to circulate the water, then a header can be used to
prevent the boiler and system pump from conflicting with each other.
NOTE
The system pump is wired with the heating demand so it will only activate when the heating is
called for. Size the system pump according to system design specifications and water content.
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boiler in the event of excessive temperature within the header due to
lack of circulation. Ideally this should be set to 90ºC.
230V Mains
Voltage
= Live
L
L
N
N = Neutral
E
E
Room
T/Stat
= Earth
Greenstar HF CDi
Double Pole
Fused Spur
L
N NS LS LR
C
Header Limit
Thermostat N
L
N
E
N
C
O
230V HW interface
‘Installer Module’
Safety isolation
L
N
N
E
4
5
6
7
8
9
10
NC
HW Heat Bank ON
CH ON
E
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
L
N
E
E
System
Pump
Page 69
Greenstar HF CDi combi
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Greenstar HF CDi
L
Frost T/Stat
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
230V HW interface
‘Installer Module’
Safety isolation
N
NC
FR FS NP LP
Page 70
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
2 x 2 Port Valves (S Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
Si Combi
L
N
N = Neutral
E
E
= Earth
M
Room
T/Stat
E
L
N
E
L
Cylinder
T/Stat
Heating
Zone Valve
C
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
~
N
N
L
= Live
L
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 71
Greenstar Si Combi
Mid Position Valve (Y Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
Mid Position
Valve
= Earth
N
Greenstar
Si Combi
Room
T/Stat
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
C
L
N
E
L
N
E
4
CH ON
L
N
E
1
5
6
7
2
8
9
10
HW OFF
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
HW ON
L
N
L
Time Controller
Page 72
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
3 x 2 Port Valves (S Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
Si Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Heating
Zone 1 Valve
C
N NS LS LR
1
L
N
E
L
N
E
L
N
E
4
CH Zone 1 ON
HW ON
5
6
7
2
8
9
10
M
CH Zone 2 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 73
Greenstar Si Combi
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
Si Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Room T/Stat
Zone 2
N
L
N
E
L
N
E
4
5
6
CH Zone 2 ON
L
N
E
N NS LS LR
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
N
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Page 74
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Room T/Stat
Zone 1
Greenstar
Si Combi
M
~
N
N
E
L
Cylinder
T/Stat
L
2
1
N
E
L
N
E
4
5
6
7
8
9
10
M
~
N
HW ON
L
N
E
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
Heating
Zone 1 Valve
C
N NS LS LR
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 75
Greenstar Si Combi
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar
Si Combi
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Radiators Zone
~
N
E
L
N
L
230V Mains
Voltage
Double Pole
Fused Spur
Radiators
Zone Valve
N NS LS LR
L
N
E
L
N
E
4
5
6
7
8
9
10
CH ON
L
N
E
L
N
E
L
N
E
N
L
Time Controller
Single Channel
Page 76
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
separate Time Controller & Room Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Series Connector
Not supplied. Once wired in, make
connector safe in electrical cover.
Room
T/Stat
Greenstar
Si Combi
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
CH ON
L
L
N
E
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 77
Greenstar Si Combi
Programmable Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
Si Combi
L
N NS LS LR
Programmable
Thermostat
N
L
C NC NO
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 78
The Link between the Live (L) and
Common (C) may already be fitted as
part of the Programmable Thermostat, if
not then a link must be wired in.
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
Si Combi
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
MAINS
L
N
E
Smartfit Layout:
Example shown S Plan configuration
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
BOILER
L
SL
S PLAN
Y PLAN
PL
N
PUMP
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
POLARITY
FREE
ACCESSORY
PORT
CYLINDER
SENSOR
HW VALVE (S)
CH VALVE (S)
Worcester wiring guide Greenstar gas-fired boilers
CYLINDER
T/STAT
Page 79
Greenstar Si Combi
Cascaded boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header
due to lack of circulation. Ideally this should be set to 90º C.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
NO
NC
C
Header Limit
Thermostat
C
N
O
N
C
230V AC
Double Pole Relay
C
N NS LS LR
NO
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
C
Greenstar
Si Combi
Greenstar
Si Combi
L
NC
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 80
Worcester wiring guide Greenstar gas-fired boilers
Greenstar Si Combi
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
Si Combi
FR FS NP LP
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
Page 81
Greenstar i Junior Combi
2 x 2 Port Valves (S Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i Jnr Combi
L
N
N = Neutral
E
E
= Earth
M
Room
T/Stat
E
L
N
E
L
Cylinder
T/Stat
Heating
Zone Valve
C
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
~
N
N
L
= Live
L
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Page 82
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i Junior Combi
Mid Position Valve (Y Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
Mid Position
Valve
= Earth
N
Greenstar
i Jnr Combi
Room
T/Stat
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
C
L
N
E
L
N
E
4
CH ON
L
N
E
1
5
6
7
2
8
9
10
HW OFF
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
HW ON
L
N
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 83
Greenstar i Junior Combi
3 x 2 Port Valves (S Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i Jnr Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Heating
Zone 1 Valve
C
N NS LS LR
1
L
N
E
L
N
E
L
N
E
4
5
6
7
2
8
CH Zone 1 ON
HW ON
9
10
M
CH Zone 2 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Page 84
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i Junior Combi
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i Jnr Combi
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Room T/Stat
Zone 2
N
L
N
E
L
N
E
4
5
6
CH Zone 2 ON
L
N
E
N NS LS LR
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
N
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 85
Greenstar i Junior Combi
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neurtal
E
E
= Earth
Room T/Stat
Zone 1
Greenstar
i Jnr Combi
M
~
N
N
E
L
Cylinder
T/Stat
L
2
1
N
E
L
N
E
4
5
6
7
8
9
10
M
~
N
HW ON
L
N
E
L
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
Heating
Zone 1 Valve
C
N NS LS LR
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Page 86
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i Junior Combi
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar
i Jnr Combi
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Radiators Zone
~
N
E
L
N
L
230V Mains
Voltage
Double Pole
Fused Spur
Radiators
Zone Valve
N NS LS LR
L
N
E
L
N
E
4
5
6
7
8
9
10
CH ON
L
N
E
L
N
E
L
N
E
N
L
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Demand
Underfloor Controls
Wiring Centre
Page 87
Greenstar i Junior Combi
separate Time Controller & Room Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
Series Connector
Not supplied. Once wired in, make
connector safe in electrical cover.
Room T/Stat
Greenstar
i Jnr Combi
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
CH ON
L
L
N
E
Time Controller
Page 88
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i Junior Combi
Programmable Thermostat
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i Jnr Combi
L
N NS LS LR
Programmable
Thermostat
N
L
C NC NO
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
The Link between the Live (L) and
Common (C) may already be fitted as
part of the Programmable Thermostat, if
not then a link must be wired in.
Page 89
Greenstar i Junior combi
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i Jnr Combi
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Smartfit Layout:
Example shown S Plan configuration
Double Pole
Fused Spur
MAINS
L
N
E
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
BOILER
L
SL
S PLAN
Y PLAN
PL
N
PUMP
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
POLARITY
FREE
ACCESSORY
PORT
CYLINDER
SENSOR
HW VALVE (S)
CH VALVE (S)
Page 90
CYLINDER
T/STAT
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i Junior combi
Cascade boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90º C.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
NO
NC
C
Header Limit
Thermostat
C
N
O
N
C
230V AC
Double Pole Relay
C
N NS LS LR
NO
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
C
Greenstar
i Jnr Combi
Greenstar
i jnr Combi
L
NC
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
Page 91
Greenstar i Junior combi
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
i Jnr Combi
FR FS NP LP
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 92
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
2 x 2 Port Valves (S Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
Greenstar
i System
= Earth
M
Room
T/Stat
E
L
N
E
Heating
Zone Valve
C
N NS LS LR
1
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
L
N
E
L
N
E
4
5
6
7
2
8
9
10
HW ON
CH ON
M
N
~
N
E
L
Cylinder
Zone Valve
L
Time Controller
Worcester wiring guide Greenstar gas-fired boilers
Page 93
Greenstar i System
Mid Position Valve (Y Plan)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Mid Position
Valve
N
Greenstar
i System
Room
T/Stat
E
Green/Yellow
Blue
White
Grey
Orange
Cylinder
T/Stat
N
C
L
N
E
L
N
E
4
CH ON
L
N
E
1
5
6
7
2
8
9
10
HW OFF
230V Mains
Voltage
Double Pole
Fused Spur
N NS LS LR
HW ON
L
N
L
Time Controller
Page 94
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
3 x 2 Port Valves (S Plan Plus)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i System
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Heating
Zone 1 Valve
C
N NS LS LR
1
L
N
E
L
N
E
L
N
E
4
CH Zone 1 ON
HW ON
5
6
7
2
8
9
10
M
CH Zone 2 ON
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
~
N
E
L
Cylinder
Zone Valve
N
M
~
N
L
E
Time Controller
3 Channel
N
L
Heating
Zone 2 Valve
Room T/Stat
Zone 2
Worcester wiring guide Greenstar gas-fired boilers
Page 95
Greenstar i System
2 x Heating Zones
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i System
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
Room T/Stat
Zone 2
N
L
N
E
L
N
E
4
5
6
CH Zone 2 ON
L
N
E
N NS LS LR
CH Zone 1 ON
230V Mains
Voltage
Double Pole
Fused Spur
N
L
Heating
Zone 1 Valve
N
L
~
N
7
8
9
10
M
~
N
E
L
Heating
Zone 2 Valve
L
Time Controller
Page 96
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
2 x 2 Port Valves & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i System
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Zone 1
E
N NS LS LR
2
N
E
L
N
E
4
5
6
7
8
9
10
M
~
N
HW ON
L
CH Zone 1 ON
L
N
E
Heating
Zone 1 Valve
C
1
230V Mains
Voltage
Double Pole
Fused Spur
L
Cylinder
T/Stat
N
L
~
N
E
L
Cylinder
Zone Valve
N
L
N
E
L
N
E
L
Time Controller
Twin Channel
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Page 97
Greenstar i System
Zoned Radiator & Underfloor Heating
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
Greenstar
i System
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
M
Room T/Stat
Radiators Zone
~
N
E
L
N
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L = Live
L
N
E
L
N
E
4
5
6
CH ON
L
Radiators
Zone Valve
N NS LS LR
N
L
Time Controller
Single Channel
Page 98
7
8
9
10
L
N
E
L
N
E
N = Neurtal
E = Earth
Demand
Underfloor Controls
Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
Single Hot Water Zone (Vented Cylinder)
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
= Live
L
L
N
N = Neutral
E
E
= Earth
Cylinder
T/Stat
Greenstar
i System
C
2
1
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
Time Controller
Single Channel
Worcester wiring guide Greenstar gas-fired boilers
Page 99
Greenstar i System
Single Heating Zone
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N = Neutral
N
E
E
= Earth
L
N
N = Neutral
E
E
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
= Earth
Room
T/Stat
Greenstar
i System
L
= Live
L
N
N NS LS LR
L
N
E
L
N
E
4
5
6
7
8
9
10
N
L
Time Controller
Single Channel
Page 100
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
Smartfit Control Pack
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Greenstar
i System
L
N NS LS LR
SMARTFIT
ROOM UNIT
230V Mains
Voltage
Double Pole
Fused Spur
MAINS
L
N
E
Smartfit Layout:
Example shown S Plan configuration
N
SMARTFIT FROST
PROTECTION
ROOM
UNIT
A
L
BOILER
L
SL
S PLAN
POLARITY
FREE
Y PLAN
PL
N
PUMP
N
L
HW
VALVE
(S)
CH
VALVE
(S)
3 PORT
VALVE
(Y)
ACCESSORY
PORT
CYLINDER
SENSOR
HW VALVE (S)
CH VALVE (S)
Worcester wiring guide Greenstar gas-fired boilers
CYLINDER
T/STAT
Page 101
Greenstar i System
Internal Diverter Valve with Worcester Controls & Unvented Cylinder
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
There is a unclarity within the Industry that in order to protect an Unvented Hot Water Cylinder from potentially
dangerous high temperatures from the boiler circuit, a 2-port motorised valve must be installed. This is not the
case, although it is the most common interpretation and approach.
FURTHER DETAILS
Building Regulation Approved Document G3, paragraph 3.6 states '…the non-self-resetting thermal cut out
should be wired to a motorised valve or some other suitable device to shut off the flow to the primary heater…'.
The latter part of this sentence can be interpreted to mean as long as we, as responsible Manufacturer's, are
confident our method provides an equal amount of protection to the common approach, we may instruct
installers of our equipment to follow a different approach. A summary is provided below.
G
The installer will use the cylinder sensor supplied with the Integral Diverter Valve kit to control the hot water
temperature.
G
The installer, therefore, will NOT need to use the hot water control thermostat of the cylinder's dual thermostat.
G
The installer may have to alter the wiring of the dual thermostat (depending on cylinder and thermostat
manufacturer) to only use the high limit thermal cut-out of the dual thermostat.
G
The high limit thermal cut out of the dual thermostat MUST be wired to interrupt the permanent live to the
Greenstar CDi System Boiler.
G
The 2-port valve supplied with the unvented cylinder will NOT be used. If it is already physically installed in
the pipe work is should be removed and electrically disconnected from the wiring centre.
Below you will find an electrical diagram for this arrangement.
Optional:
Third Party Room Thermostat:
Using the Worcester Internal DT20
Timer an External Third Party Room
Thermostat must be connected to
the boiler on the External Controls
section of ST10 (NS, LS & LR).
DUAL THERMOSTAT
230V MAINS
SUPPLY
SAFETY LIMIT
THERMOSTAT
N E L
Brown
OPTIONAL:
THIRD PARTY
ROOM THERMOSTAT
COM
(made safe)
CYLINDER
THERMOSTAT
Brown
Blue
CALL
Connector
Block
Green\Yellow
N
ST8
9
8
LR LS NS N
L
FR FS NP LP
ST10
7
NOTE:
Leave the link if using Worcester
Internal Digital RF units.
ST6
Pump
Harness
Fan
Harness
FR FS NP LP
L
N NS LS LR
9
8
7
S11
2.5 A 230 V AC
DIVERTER VALVE
MOTOR PLUG
Main
Harness
S12
0.5 A
S13
1.6 A
Code Plug
Page 102
Worcester wiring guide Greenstar gas-fired boilers
Greenstar i System
Cascade boilers with low loss header
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
HEADER LIMIT THERMOSTAT
This cuts the Demand to the boilers in the event of excessive temperature within the Header due
to lack of circulation. Ideally this should be set to 90º C.
Wiring from Zone/s Controls
IMPORTANT NOTE:
The Relay should be mounted
within a suitable electrically safe
housing.
Junction Box/Wiring Centre
L
N
Switched Live/
Demand
E
N
C
230V AC
Double Pole Relay
C
N NS LS LR
NC
NO
C
Coil
Coil
Live
Neutral
Example relay shown is a Double
Pole Mains Voltage Relay. This
isolates the Boilers electrically in
case of a fault condition.
C
Greenstar
i System
L
NC
C
Header Limit
Thermostat
C
N
O
NO
Greenstar
i System
L
N NS LS LR
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Worcester wiring guide Greenstar gas-fired boilers
Page 103
Greenstar i System
Frost Protection
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
The boiler has inbuilt frost protection. When the primary temperature drops below 8°C the pump is switched
on. When then temperature rises above 9°C the pump switches off after a 3 minute pump overrun. If the
primary temperature drops below 5°C, a central heating demand is activated until the primary temperature
rises above 12 °C. The demand switches off followed by the pump after a 3 minute overrun.
The boiler has the facility to connect an external frost protection device to protect in “at risk areas” (terminal
block ST6, contacts FS and FR). This is used if the boiler is not located in the area needing protection i.e. boiler
in kitchen but pipe work in the garage that needs frost protection.
If external frost thermostat is calling, i.e. temperature within frost thermostat below the set point, but the
primary temperature of the boiler is above 5°C, the pump will run until the temperature within the frost
thermostat rises above the set point. If external frost thermostat is calling and the primary temperature is
below 5°C, a central heating demand is activated until primary temperature is above 12 °C. If the frost
thermostat is still calling the pump will run until the temperature within the frost thermostat location rises
above the set point.
Frost T/Stat
Greenstar
i System
FR FS NP LP
L
230V Mains
Voltage
Double Pole
Fused Spur
L
N
E
Page 104
N NS LS LR
Earth to Wiring Centre
Neutral Feed to Wiring Centre
Live Feed to Wiring Centre
Switch Live from Wiring Centre
Worcester wiring guide Greenstar gas-fired boilers
Worcester wiring guide Greenstar gas-fired boilers
Page 105
Worcester wiring guide Greenstar gas-fired boilers
Page 106
Useful Numbers
The generic Live, Neutral and Earth feed/s to equipment must return
to the respective connection on the wiring centre.
These connections are denoted as follows:
L
L
= Live
N
N = Neutral
E
E
= Earth
Sales
Tel:
01905 752640
Contracts
Tel:
0844 892 2332
sales.mailbox@uk.bosch.com
service-contract.worcester@uk.bosch.com
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Tel:
01905 752576
Contact Centre
Tel:
0844 892 3000
spares.mailbox@uk.bosch.com
general.worcester@uk.bosch.com
Training
Tel:
01905 752526
Monday – Friday 7.00am – 8.00pm
Saturday 8.00am – 5.00pm
Sunday 9.00am – 12 noon
training@uk.bosch.com
Literature
Tel:
0844 892 9800
literature@uk.bosch.com
or download instantly from our website
Technical Support
Tel:
0844 892 3366
technical.enquiries@uk.bosch.com
Monday – Friday 7.00am – 8.00pm
Saturday 8.30am – 4.00pm
www.worcester-bosch.co.uk
Calls to the listed 0844 numbers are charged at up to 3 pence per minute from BT landlines.
Calls from mobiles and some networks may vary. Calls to and from Bosch Thermotechnology Ltd.
may be recorded for training and quality assurance purposes.
Worcester, Bosch Group is a brand name of Bosch Thermotechnology Ltd.
This is leaflet is accurate at the date of printing, buy may be superseded and should
be disregarded if specification and/or appearances are changed in the interest of
continued improvement. The statutory rights of the consumer are not affected.
6 720 646 965 Issue A (09/11)
Worcester, Bosch Group, Cotswold Way,
Warndon, Worcester, WR4 9SW.
Tel: 0844 892 9900