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7.6
Connection of control and sensor cables
NOTICE
EMS-BUS and CAN-BUS are not compatible!
▶ Only connect CAN-BUS and EMS-BUS wiring to the correct
connectors in the control box.
7.6.1
Installation/replacement of low voltage cables
• All low voltage cables are connected to the XCU-THH board. Access is
gained as described in 7.4
• Cables for accessories should be fed through the bottom left area of
the control box fig 26 and connected to the XCU-THH control unit as
described in 7.6.6
• A white bracket is fixed to each side of control board XCU-SEH. This
incorporates pairs of cut-outs to enable the low voltage cables (from
the XCU-THH board) to be securely fixed by cable ties for strain relief
purposes.
• Attach cable to cable-tie bracket, to ensure 100N pull resistance, as
follows: ensuring sufficient slack of cable to the board, fix a 3.6mm-
wide cable tie to the cable and secure it to the plate with two 2.5mm-
wide ties as in show in fig 33. The heads of the ties must not be on the
same side of the plate. This ensures minimum movement of cable.
• Fit white bung around cable beneath control box and push bung into
control box hole.
• Any replaced cable must follow installation information above
3.6mm
cable tie
Cable
Fig. 33 Cable installation in cable bracket
7.6.2
CAN-BUS
NOTICE
The system will be damaged if the 24VDC- and the CAN-BUS
connections are incorrectly connected!
The communication circuits are not designed for 24VDC constant
voltage.
▶ Check to ensure that the cables are connected to the contacts with
the corresponding markings on the modules.
NOTICE
Malfunction due to mixed up connections!
If the "High" (H) and "Low" (L) connections are mixed up, there is no
communication between the heat pump and the indoor unit.
▶ Check to ensure that the cables are connected to the connections
with the corresponding markings in both ends of the CAN-BUS cable.
Pre plumbed cylinder – 6 721 852 928 (2023/04)
Slots in
2.5mm
bracket
cable tie
0010049380-001
A
Vcc
Vcc
H
H
L
L
GND
GND
Fig. 34 CAN-BUS heat pump - indoor unit
[A]
Heat pump
[B]
Indoor unit
[Vcc]
24V= (24VDC)
[H]
HIGH
[L]
LOW
[GND]
gnd
The heat pump and indoor unit are connected to each other by a
communication line, the CAN-BUS [24VDC, class III (SELV)].
A LIYCY cable (TP) 2 x 2 x 0.75 (or equivalent) is suitable as an
extension cable outside of the unit. In doing so, only earth the
shielding on one side (indoor unit) and to the casing.
The maximum permissible cable length is 30 m.
The connection is made with four wires, as the 24VDC supply is also
connected. The 24VDC and CAN-BUS connections are marked on the
module.
The CANBUS cable has two pairs of twisted wires. Vcc and GND is one
pair, H and L is the second pair. Maximum cable insulation striping length
for all cables is 120mm. Maximum wire striping is between 8-10mm.
≤120 mm
≤10 mm
Fig. 35 Wire striping CAN-BUS
Electrical connection
B
0010049010-001
0010041915-001
29
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