Existing Installations - Worcester GREENSTAR 24 Installation, Commissioning And Servicing Instructions

Electrical
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. 43 Two room thermostats, one integrated timer
Wire these points to
L
Wire these points to
N
Wire these points to
E
Table 15 Connection legend
5.3.3

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.
230V ROOM STAT/CLOCK ST10
Room Thermostat
1
Fig. 44 Room Thermostat and programmers
1 Series connector, not supplied.
Connector to be made safe.
Table 16
26
M
~
N
L
E
L
Zone 2
Zone Valve
L
N
230V
MAINS
SUPPLY
8
9 10
E
L L N L
N
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 L
N
R S S
ST10
ROOM THERMOSTAT ONLY
DT20 Twin Channel
Room Thermostat
Programmer
OR
MT10 Mechanical
Timer
13
12
9 3
6
on
on
off
off
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
N L C
switched live
1
Fig. 45 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.
Table 17
▶ Remove the link between LR and LS.
▶ Connect external controls LIVE supply to terminal LS
▶ Connect external controls LIVE return to terminal LR
'Call for Heat' or 'Switched Live'.
▶ Connect external controls NEUTRAL to terminal NS
Some devices do not require connection ofa neutral i.e.
battery powered devices.
230V
MAINS
SUPPLY
N E L
neutral
live
switched live
L L N N L
R S S
ST10
6720643895-41.1Wo
230V
MAINS
SUPPLY
N E L
NC NO
live
neutral
L L N L
N
R S
S
ST10
6 720 811 922 (2014/07)