4
3
N
L
N
L
4
23
IMPORTANT Ensure that all cords
pass through the terminal box
entrance grommets and are securely
fixed by the cable clamps. Ensure that
the power supply cord is connected
such that the current carrying conduc-
tors become taut before the earthing
conductor should the supply cord slip
from the cable clamp.
Refit the terminal box cover after com-
pletition of all electrical connections.
4.9 Controls
4.9.1 External electrical
controls
The boiler terminals 3,4 and 5 for
connecting external controls such as a
timeswitch and/or room thermostat.
Terminals 3 and 4 are linked together
when the boiler is supplied. If external
controls are used, this link (3, fig.30)
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 4.9.2 for full connec-
tion details.
4.9.2 Connection of external
electric controls
4.9.2.1 Connection details for pro-
grammable thermostat and boiler
terminal strip.
Fig. 31 shows the connection details
where a programmable thermostat
(time switch with built-in room ther-
mostat) is used to control the boiler.
(Important: The arrowed numbers indi-
cate connection into the relevant ter-
minal in the boiler terminal strip).
4.9.2.2 Connection details for exter-
nal time switches and boiler terminal
strip.
Fig. 32 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 connec-
ted 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. 33)
→
→
→
→
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. 32
fig. 33
GW 409/0
Boiler Terminal Strip
E
N
L
1
2
3
4
5
6
ON
OFF
N
L
4
3
→
→
→
→
E
N
L
1
2
3
4
5
6
ON
OFF
N
L
4
3
→
→
→
→
→
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
Pet 1
fig. 31
N
L
4
3
→
→
→
→
N
L
1
2
3
4
N
L
3
4
→
→
→
→
N
L
1
2
3
4
OFF
ON
3
4
5
→
→
→
→
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
ON
OFF
3
4
→
→
Q1
Q2
Connection details for external time switches and boiler terminal strip
Connection details for programmable thermostat and boiler terminal strip
