Carrier 40MBDAQ - Page 29

40MBDAQ: Service Manual
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29
DIAGNOSIS AND SOLUTION (CONT.)
E8 (Communication error between master and slave unit (for twins system) Diagnosis and Solution)
Description: When set in the twins system, the master unit and slave unit cannot be recognized normally.
Recommended parts to prepare:
• Connection wires
• Indoor PCB
Troubleshooting
.
Check
the dial switch
settings of the master unit
and the slave unit.
Are they correct?
C
orrect t
h
e setting
s
Correct the settings.
No
Check
the
PQE communication wires
connection. Is it properly
wired?
Yes
Correct the wire connections.
No
One of the 2 indoor PCBs is defective.
Connect only one indoor unit to
the outdoor unit separately.
The one that displays an
E1 error code is defective.
Yes