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Procedure 2: replacing P.C. board
1
Replace the faulty P.C. board with a service P.C. board.
Be sure to replicate the old jumper setting (removal), and connector short-circuit setting (e.g. CN030) on
the service P.C. board. (See the diagram at below.)
If a short-circuiting plug had been used on the replaced
P.C. board, reuse it on the service P.C. board.
(MCC-1403)
CN041
CN030
Remove group control wiring from terminals
A and B of indoor unit being serviced, and
connect remote control wiring.
Indoor unit (one being serviced)
Service P.C. board
Indoor unit
P.C. board
Remote control
Group control wiring
Remove CN041
connectors of all
other indoor units
in same group.
Case 1
A B
Indoor unit
P.C. board
A B
A B
Indoor unit (one being serviced)
Service P.C. board
Indoor unit
P.C. board
CN
041
Remote control
Group control wiring
Case 2
A B
Indoor unit
P.C. board
A B
A B
2
It is necessary to establish a one-to-one correspondence between the indoor unit being
serviced and the remote control.
Turn on the indoor unit using one of the methods described below according to the system configuration.
(1)Single (stand-alone) operation
Turn on the indoor unit and proceed to
Procedure 3
.
(2) Group operation
A) If it is possible to selectively turn on the indoor unit being serviced
Turn on the indoor unit being serviced and proceed to
Procedure 3
.
B) If it is not possible to selectively turn on the indoor unit being serviced (
Case 1
)
a) Temporarily disconnect the group control wiring from terminals A and B of the indoor unit being
serviced.
b) Connect the remote control wiring to the terminals, turn on the indoor unit, and proceed to
Procedure 3
.
* If this method cannot be used, proceed to the alternative method described below (
Case 2
).
C) If it is not possible to selectively turn on the indoor unit being serviced (
Case 2
)
a) Remove the CN041 connectors of all other indoor units in the same group.
b) Turn on the indoor unit and proceed to
Procedure 3
.
* Be sure to restore the temporarily removed group control wiring and CN041 connectors to their initial states
after Procedure 3 has been completed.
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