Electrical
6 720 811 922 (2014/07)26
INTEGRATED TIMER AND TWO ZONES
Fig. 43 Two room thermostats, one integrated timer
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
Fig. 44 Room Thermostat and programmers
ROOM THERMOSTAT ONLY
PROGRAMMABLE THERMOSTAT
Fig. 45 Programmable thermostat
▶ Remove the link between LR and LS.
▶ Connect external controls LIVE supply to terminal LS
▶ Connect external controls LIVE return to terminal LR
▶Connect external controls NEUTRAL to terminal NS
Wire these points to this point
Wire these points to this point
Wire these points to this point
Table 15 Connection legend
1 Series connector, not supplied.
Connector to be made safe.
Table 16
ST10
Plug in
Worcester timer.
(see timer operating
instructions for
installation)
LNE4
56
78
910
E
N
L
6720643895-124.1Wo
N
Zone 1
Room Thermostat
N
Zone 2
Room Thermostat
M
~
L
N
E
Zone 1
Zone Valve
M
~
L
N
E
Zone 2
Zone Valve
L
L
L
N
S
N
L
S
L
R
blue
brown
green/yellow
E
230V
MAINS
SUPPLY
L
N
S
N
L
S
L
R
N
blue
brown
green/yellow
live
switched live
neutral
E
ST10
230V
MAINS
SUPPLY
L
Room Thermostat
Programmer
M
1
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.
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
‘Call for Heat’ or ‘Switched Live’.
Some devices do not require connection ofa neutral i.e.
battery powered devices.
OR
L
N
S
N
L
S
L
R
N
blue
brown
green/yellow
live
switched live
neutral
E
ST10
230V
MAINS
SUPPLY
L
Room Thermostat
DT20 Twin Channel
Programmer
MT10 Mechanical
Timer
12
3
6
9
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
on
off
off
on
6720643895-41.1Wo
L
N
S
N
L
SLR
N
blue
brown
green/yellow
live
switched live
neutral
E
ST10
230V
MAINS
SUPPLY
L
Programmable
Thermostat
NL
CNCNO
1
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