22
British Gas RD1
-
Installation & Servicing
INSTALLATION
L
N
L
N
N
EC2
EC1
Terminal block
switch live
Terminal block
permanent live
Clock
Room thermostat
Cla 1792
33 EXTERNAL CONTROLS
The wiring diagrams illustrated in Frames 35-37 cover the
systems most likely to be fitted to this appliance.
For wiring external controls to the boiler, reference should
be made to the system wiring diagrams supplied by the
relevant manufacturer, in conjunction with the wiring
diagrams shown in Frames 35-37.
Difficulty in wiring should not arise, providing the following
directions are observed:
1. Preferred wiring method.
Controls that switch the system on or off, e.g. a time
switch, must be wired, in series and terminate with a volt
free contact across EC1/EC2.
2. Alternative wiring method.
A switched live supply may be connected to EC1
(leaving EC2 without connection), which must be fused
at 2A Maximum.
IMPORTANT.
A link wire between terminals EC1 and EC2 is not
acceptable.
Notes.
a. Route the cable to terminal EC1 and EC2 from the
RHS of the boiler.
b. The terminal plate may be unscrewed from the
controls support to improve access for connection.
3. Controls that override an on/off control, e.g. frost
thermostat must be wired, in parallel, with the control(s)
to be overridden. Refer to Frame 38.
4. If a proprietary system is used, follow the instructions
supplied by the manufacturer.
Advice on required modifications to the wiring may be
obtained from the component manufacturers.
Volt Free Contacts
If switched live is connected here (EC1) leave other terminal without
connection. If programmer is used here (EC1) the switched live MUST
BE FUSED AT 2A MAXIMUM.
Detection
HSI
Return
sensor
sensor
Flow
Flue
sensor
All EARTHS must be connected
(Not all earths are shown for clarity)
Boiler control
potentiometer
NEW
Modem
LED 1 LED 2
LED 3
LED 4
Fuse
L
Mains
L
L
N
N
N
Cla 61
18
pk
y
w
Fan
Gas
valve
Air pressure switch
Pump
NC
NO
com
pk
y r
bk
r
w w
b br
EC1 EC2
O/heat thermostat
Reset
Link
gy w y y
or or
r
r
r
r
b
b
w
w
LEGEND
b
blue
bk black
br brown
r
red
y
yellow
w white
32 FLOW WIRING DIAGRAM
gy grey
or orange
v
violet
pk pink
g/y green/yellow
L
N
L N
EC2
Terminal block
switch live
Terminal block
permanent live
Clock
Room thermostat
EC1
2A
Cla 1793
5. On completion of all wiring connections, relocate the control
box and secure.
Notes.
1.
Connection between a frost thermostat and the time control
should be made without disturbing other wiring.
2.
A frost thermostat should be sited in a cool place in the house,
but where it can sense heat from the system.
Preferred Wiring Method.
Alternative Wiring Method.
INST
ALLA
TION
