5.8.3.
Access to the connector block / Boiler HMI
The connection box with instrument panel is supplied separately as
standard with this unit. The connection box must be connected to the
automatic control unit using the cable supplied. To do this, proceed
as follows:
Under the boiler, there is a cable with a connector for the
control unit.
1. Carefully open the latch on the rear of the connection box using a
screwdriver.
2. Open the cover of the connection box.
3. Disconnect a pull relief clip. Turn the pull relief clip round.
4. Insert the plug from the cable into the
HMI
plug on the PCB for the
connection box.
5. Press the pull relief clip firmly into place.
6. Now connect the required external controllers to the remaining
connectors. To do this, proceed as follows:
- Disconnect a pull relief clip.
- Turn the pull relief clip round.
- Place the cable underneath the pull relief clip.
- Press the pull relief clip firmly into place.
- Connect the connection box and check that the box is sealed
properly.
7. Slide the User instruction card supplied into the guides underneath
the connection box.
8. Slide the connection box into the guides underneath the boiler
once all the connections have been made.
9. Secure the connection box using the screw found in the guides.
The connection box can also be attached to the wall using
the screw holes on the back of the connection box. The
connection box should be screwed to the wall using the
fixing points inside the unit.
The connection options for external system controls to the boiler HMI
are explained in the following paragraphs.
)
For more detailed information, see: Connecting
External Controls Sheet.
5.8.4.
Connection options
Various external thermostats and controllers can be connected to the
control PCB.
A
Mains voltage
B
Low voltage
On/off-OT
connection is only suitable for:
4
24V power stealing thermostat
4
Potential free on/off thermostat
4
OT thermostat (iSense or qSense)
R000411-C
8
9
7
6
4
SCU
HMI
OT
On/of
BUS
BUS
5
3
2
1
R000734-A
1
2
3
4
5
6
3
4
1
2
1
2
1
2
3
On/off
OT
Enable
+
-
+
-
CH
DHW
Status
Nc C No
Tout Tdhw BL
SCU
BUS
BUS
HMI
A
B
5. Installation
Baxi MainEco Combi and System 24 - 28 - 35 / 18 - 24
34
02092014 - 7619497-02