Carrier X-POWER Series Service Manual page 147

Carrier service manual
4.2 E2: Indoor units and master unit communication error (Only display on master unit, all the ODU
in standby)
E2: Indoor units and master
unit communication error
Communication wires P, Q, E are short
circuit or disconnected (Measure the
resistance among P, Q and E, the normal
resistance between P and Q is 120Ω)
No
Communication wires
connected in line shape
No
The communication wires are interfered
by high voltage power (voltage over
is high voltage power)
208-230V
No
Communication wires are close to
electromagnetic interference source.
Such as transfer, strong fluorescent
lamp, etc.
No
The length of communication wire is
over 1200m
No
Outdoor main control board is
damaged
Troubleshooting
Yes
Yes
are not
Yes
Yes
Yes
Reconnect the communication
wires
Connect the communication wires
in line shape
Ensure the communication wires and
high voltage wires do not twining
Remove the interference source, or
use device to filter out the interference
Adjust the wire length to less than
1200m or strengthen the signal
Replace outdoor main control board
R410A DC Inverter Series
165