Worcester GREENSTAR 24i Junior Installation, Commissioning And Servicing Instructions page 29

INTEGRATED TIMER AND TWO ZONES
Zone 1
Zone Valve
M
~
N
E
Zone 1 Zone 2
Room Thermostat Room Thermostat
L
N
L N E
L N E 4
5 6 7
Plug in
Worcester timer.
(see timer operating
instructions for
installation)
Fig. 55 Two room thermostats, one integrated timer
Wire these points to
L
Wire these points to
N
Wire these points to
E
Table 16 Connection legend
EXISTING INSTALLATIONS
For boiler replacements on an existing system, it is not necessary to zone
the upstairs and downstairs separately, compliance with the zone
requirements can be achieved by a single room thermostat or
programmable room thermostat.
While the system is drained down, TRVs must be fitted to all rooms
except the bathrooms and the room with the thermostat.
The following figures show the options of room thermostat with
programmer, room thermostat only or programmable thermostat.
ROOM THERMOSTAT AND PROGRAMMER:
Room Thermostat
1
Fig. 56 Room thermostat and programmer
1 Series connector, not supplied.
Connector to be made safe.
6 720 802 047 (2013/05)
M
~
N
L
E L
Zone 2
Zone Valve
L
N
230V
MAINS
SUPPLY
8 9 10
E
L L N N L
R S S
ST10
this point
L
this point
N
this point
E
230V
Programmer
MAINS
SUPPLY
M
N E L
neutral
live
switched live
L L N N L
R S S
ST10
6720643895-42.1Wo
ROOM THERMOSTAT ONLY
Programmer
OR
MT10 Mechanical
Timer
13
12
9 3
6
on
on
off
off
Fig. 57 Room thermostat only
PROGRAMMABLE THERMOSTAT
The programmable thermostat may be a hard wired or
RF type.
This diagram is applicable for the hard wired unit and the
receiver section of the RF pack.
Programmable
Thermostat
C
N L
switched live
1
Fig. 58 Programmable thermostat
1 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.
▶ Remove the link between L and L
R
▶ Connect external controls LIVE supply to terminal L
▶ Connect external controls LIVE return to terminal L
Live Return (L ) is sometimes referred to as
R
'Call for Heat' or 'Switched Live'.
▶ Connect external controls NEUTRAL to terminal N
Some devices do not require connection of a neutral i.e.
battery powered devices.
INSTALLATION
MAINS
SUPPLY
N E L
neutral
live
switched live
L L N N L
R S S
ST10
230V
MAINS
SUPPLY
N E L
NC NO
live
neutral
L L N N L
R S S
ST10
.
S
S
R
S
29