Carrier 38MBQ Series - Communication Error Diagnosis; Troubleshooting E1 Error

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DIAGNOSIS AND SOLUTION (CONT)
Table 19—Indoor/Outdoor Unit Communication Error − Diagnosis and Solution (E1)
Error Code E1
Malfunction decision conditions
Indoor unit does not receive feedback from outdoor unit for 60 seconds, or the outdoor unit does
not receive feedback from indoor unit for 120 seconds.
Supposed causes
S Wiring mistakes
S Faulty indoor or outdoor PCB
Troubleshooting:
No
Yes
Yes
Yes
No
No
Yes
No
E1 displayed
Communication malfunction between
the indoor and outdoor units
Power o, wait for 2 minutes then
restart the unit. Does the problem
still exist?
Is there any interference such as
too many lamps or power
transformers? Or is the signal wire
too long?
Yes
Remove the interference or add
a magnet ring on the power wire
No
Is the signal wire a shield cable
and is the shield cable a
earthing?
Adopt a shield cable/shield cable
earthing
Is the signal wire broken?
Replace the signal wire
Are the signal wires properly
inserted on the PCB?
Replace the indoor main PCB, is the
error resolved?
Replace the outdoor main PCB.
Pull out and insert back