N
L
4
3
N
L
4
3
3
4
5
20
4
3
N
L
N
L
4
4.8 Controls
4.8.1 External electrical controls
The boiler terminals 3,4 and 5 are for
connecting external controls such as a
time switch and/or room thermostat.
Terminals 3 and 4 are linked together
when the boiler is supplied. If external
controls are used, this link must be
removed, and the controls connected
across terminals 3 and 4.
Terminal 5 is an additional neutral
connection for external neutrals such
as from the anticipator of a room
thermostat.
Refer to Section 4.8.2 for full
connection details.
4.8.2 Connection of external electrical
controls
4.8.2.1 Connection details for
programmable thermostat and boiler
terminal strip (refer to fig. 29).
Fig. 29 shows the connection details
where a programmable thermostat
(time switch with built-in room
thermostat) is used to control the
boiler. (Important: The arrowed
numbers indicate connection into the
relevant terminal in the boiler terminal
strip).
4.8.2.2 Connection details for
external time switches and boiler
terminal strip (refer to fig 29a).
Fig. 29a shows the connection details
where a time switch is used without a
room thermostat to control the boiler.
(Important: The arrowed numbers
indicate connection into the relevant
terminal in the boiler terminal strip).
If a room thermostat is to be connected
in addition to a time switch the wire
between the time switch 'ON' terminal
and boiler terminal 4 should be broken
by the contacts of the room thermostat
(see Schematic layout, fig. 30).
If a frost thermostat is to be fitted it
should be connected in parallel across
terminals 3 and 4.
4.8.2.3 Vaillant optional Plug-in timer
Accessories
Refer to the instructions supplied with
the optional plug in timer accessories
for connection details.
→
→
→
→
ACL Drayton
Lifestyle
LP711
ACL Drayton
Switchmaster 300
(Please note: Remove Link N-2 and L-4)
Grässlin Towerchron
Dt71, T200l
Honeywell
ST6100
Honeywell
ST7000B
(Battery operated)
Horstmann
425 Coronet
Channel Plus, H17, H11
Landis & Gyr
RWB100, 152, 170
Potterton Myson
EP400l, EP500l
Danfoss Randall
103, 103E, 103E7
Danfoss Randall
Set 1E, TS975
fig. 29 a
7
5
4
3
MAINS
SUPPLY
230 V
50 Hz
L
L
L
N
N
N
N
20 V
DO NOT USE!
3 A FUSE
SWITCH
CONTACTS
ROOM
THERMOSTAT
CLOCK
8 9
fig. 30
GW 409/1
Boiler Terminal Strip
E
N
L
1
2
3
4
5
6
ON
OFF
→
→
→
→
E
N
L
1
2
3
4
5
6
ON
OFF
→
→
→
→
→
N
L
1
2
3
4
5
E
OFF
ON
N
L
3
4
→
→
→
→
→
→
→
→
→
→
N
L
1
2
3
4
1
2
3
E
5
6
ON
N
L
3
4
→
→
→
→
N
L
1
2
3
4
OFF
ON
N
L
4
3
→
→
→
→
N
L
1
2
3
4
ON
N
L
3
4
→
→
→
→
N
L
1
2
3
4
ON
N
L
3
4
→
→
→
→
N
L
1
2
3
4
3
4
→
→
L
2
3
4
OFF
ON
Vaillant Calotrol
(VRT 9083 and VRT 9084)
ACL Drayton
Digistat 2 and 3
ACL Drayton
PT110, PT170
ACL Drayton
Lifestyle
CT171, CT172,
PT271, PT371
Danfoss Randall
TP2, TP3, TP4, TP5
Honeywell
CM51, CM41
Landis & Gyr
REV 10 and 21
Potterton Myson
Pot 1
fig. 29
N
L
4
3
→
→
→
→
N
L
1
2
3
4
N
L
3
→
→
→
N
L
1
2
3
4
OFF
ON
→
→
→
→
2
L
1
N
C
OFF
ON
N
L
3
4
→
→
→
→
1
2
3
4
3
4
→
→
1
2
3
3
4
→
→
1
2
3
3
4
→
→
A
B
C
3
4
→
→
Q1
Q2
Connection detail for room thermostat and time switch
Connection details for time switch
Connection details for programmable thermostats
