Carrier 38QUS012D8S Service Manual page 120

2.4.3 Units with TWINS Function (for the Super-Slim Cassette & A5 Duct)
2.4.3.1 Communication
E8
F3 Displayed
F3 Displayed
Communication failure between
Communication failure between
master unit and slave unit
master unit and slave unit
Check the dial switch settings of
Check the dial switch settings of
master unit and slave unit. Are they
master unit and slave unit. Are they
correct?
correct?
Check the PQE communication wires
Check the PQE communication wires
connection, is it wired properly?
connection, is it wired properly?
One of the 2 indoor PCBs is defective.
One of the 2 indoor PCBs is defective.
Connect only one indoor unit to the outdoor
Connect only one indoor unit to the outdoor
unit separately. The one that displays an E1
unit separately. The one that displays an E1
error code is defective
error code is defective
2.4.3.2 Other Malfunction between Master Unit and Indoor Unit
One indoor unit displays "E9", which means the other indoor unit is faulty. Check the other indoor unit's error
code and then follow the prescribed solutions to resolve the malfunction.
Electrical Control System
between Master Unit and Indoor Unit
Malfunction
Yes
Yes
Correct the
Correct the
No
settings
settings
Correct the wire
Correct the wire
No
connections
connections
Troubleshooting
118