Electrical Connections Of The Boiler; Connecting A Room Thermostat; Filling The Installation; Flushing The System - Baxi COMBI 224 Installation And Service Manual

Fig.38 Electrical connections
B
W R Bk Br
Br Bl
Gn Bk R
Gy W Vt
1 2 3 4 5 1 2 3 4 5 6 7 1 2
X12 X11 X10 X5
B
J X8 X14 X7
X9
OS
OT
X13
L-BUS
On
SERVICE
Off
3 2 1
6.6

Filling the installation

7661586 - 2 - 12072016
TIMER
Bl G/Y
Br
Bl Bk
Gy Br
1 1 2 3
X3 X2
X1 MAINS
X6 X4 F2
N L
RT 0.5A
230V - 50Hz
PN-0000274

6.5.2 Electrical connections of the boiler

Access the connection board located below the control panel to make the
electrical connections by:
1. Fully unscrewing the two screws retaining the electrical cover at the
bottom of the front panel and then remove the cover.
2. Connect the electrical power supply to the X1 terminal on the con­
nection board as shown on the label located on the inside of the
electrical cover. Route the cables to the rear using the integral chan­
nel guides. Additional cable ties can be used if 5–core cable is used.
Note
The blue X1 Mains terminal block can be removed to ease the ac­
cess for wiring.
X1 Electrical power supply 230V~50Hz
X4 230V Room thermostat (remove the link)
X6 Not used
X7 Not used
X8 On/Off — R-Bus — Low voltage/voltage free Room thermostat (re­
move the link)
X9 Service connection (PC)
X13 L-Bus connection
X14 Outside sensor (OS) connection
1. Outside sensor
2. Common
J Dip-switch
1. Maximum heating temperature: OFF = 80°C = 45°C (floor sys­
tem)
2. OFF = Maximum output (heating) — ON = Boiler output 50%
(heating)
3. DO NOT ADJUST!
See
For more information see section 3.2.4 Electrical diagram.

6.5.3 Connecting a room thermostat

The terminals can be accessed by removing the electrical cover as descri­
bed in 6.5.1 Electrical connections of the boiler.
230V Room Thermostat
When using a 230V Room Thermostat it must be connected to Terminal
X4 on circuit board B. See diagram.
The X4 link wire must be removed from the terminal.
Note
The X4 terminal block for the 230V Room Thermostat can be re­
moved to ease the access for wiring.
Low Voltage/Voltage Free Room Thermostat
These connections are not polarity sensitive.
When using a Low voltage/Voltage free Open Therm type room thermostat
it must be connected to Terminal X8 on connection board B. See diagram.
The X8 link wire must be removed from the terminal.
Replace the electrical cover and secure with the 2 screws.

6.6.1 Flushing the system

Flush thoroughly and treat the system according to guidance given in BS
7593.
6 Installation
43