Haier MRV 5 Series Troubleshooting Manual page 181

Standard:
1. The communication wire is a
double core* (0.75-2)mm2 shielded
wire， no polarity.
2.The shield layer of outdoor unit is
grounded, or the shied layer of the
farthest indoor unit is grounded;
3.The shield layer between each
indoor unit must be connected
together;
4. The shielding layer should not be
too long, can't be shorted with PQ,
can't touch the PCB;
5. PQ internal copper wire and shield
can not be connected ;
6.The communication wire and the
power supply wire are kept at a
distance of 20cm and are protected
by PVC or galvanized pipe.
7. The total length ≤ 1500m,the
diameter of the wire is 0.75mm2.
shielded layer
8. All the connection points must be
done with termina block.
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